I think Kentucky and the Indian Territory are likely to end up in the CSA after the war, most of KY wanted to leave and it will be a difficult task to keep that state in the Union.
In OTL, most of Kentucky had no desire to fight for the Confederacy. This was shown repeatedly when Confederate Armies invaded the state expecting volunteers to flock to the colors. Far from obtaining Kentucky, an independent CSA is going to be lucky to keep Arkansas and Tennessee.
Indian Territory was deeply divided with forces fighting on both the Union and Confederate sides, but it did seem slightly more pro-Confederate. Expect this to last until a Confederate leader proposes a new Trail of Tears or even enslavement of the Indians.
The CSA will have an industrial base on an axis from Birmingham, AL to Atlanta, GA to about Greensville, SC connected by railways.
The Confederate industrial base was in the border states. Alabama, Georgia, and South Carolina combined had less industry than Virginia.
The Confederate rail system was falling apart long before Union armies started marching through the deep south. The Confederate government dictated rates to the railroads, which meant the railroads were unable to properly maintain or replace rails or rolling stock. It will take years for the railroads to be restored to pre-war operating condition.
There was a banking system in the South but it was focused on New Orleans, which was taken so early in the war as to eliminate it from playing a part in the Southern war effort.
New Orleans was the only part of the Confederate banking system with much hard currency, but most of that was gone before New Orleans fell. Confederate fiscal policy led to runaway inflation and massive public debts.
Southern industry will grow, though not at the rate of the Great Lakes or New England.
An unintended effect of the Union blockade was it provided protectionism for Confederate industry. Post-war, Confederate industry will have compete with foreign manufactures. Also the CSA military’s post-war need for manufactured goods will drop dramatically. Confederate industry is in for some rocky times in the first years after the war.
There will be expansion by the Confederacy though, especially into Cuba, probably into northern Mexico (they met with the governors of the border states from Tamapulias to Sonora in the late 1861 timeframe and at least one was ready to join before the ARizona situation came up). I could see adventures into Central America as well, eventually we see a smattering of grey in Latin America. Cuba certainly, perhaps the Yucatan and Hispanola, and possibly Nicaragua, Costa Rica, Guatemala, El Salvarod, the old Republic of the Rio Grande, and Honduras as well.
The population of none of these states want to be Confederate. Most are rife with tropical diseases that will kill Confederates in droves. The Confederacy does not have and cannot afford a blue-water navy. In OTL, all Confederate attempts to acquire enemy territory failed miserably. Every one of these risks US involvement, leading to a two-front war for the Confederacy. Most risk war with a major European power.
Mexico has a larger free population than the Confederacy and cannot be blockaded by them. If the French are still in Mexico, things get really sticky for the Confederates.
The only certain thing about an attempt to seize Cuba is that Spain has a real navy, is significantly more powerful, and has historical claim to a lot of the Confederacy.
The one thing that could be counted on to get Central America to work together was invasion by pro-slavery forces, typically with passive support by the British. This is the best chance the Confederacy has for acquiring foreign territory, but it will take a lot longer to pacify than the Confederates expect.
The Confederacy cannot afford the blood and treasure for any of these foreign ventures, but I expect them to try for at least some of these. Odd are highly in favor of Confederate failure, and even if they succeed the main product of these colonies will be dead Confederates.
Slavery will not last into the 20th century. Britain offered recognition of the Confederacy in 1862 if they would abandon slavery and they said no. But if cut off from trade with Europe it will die quietly, perhaps on the eve of the 20th century or 1890.
If the Confederacy resists British pressure to end slavery as long as OTL’s Brazil, then the Confederacy will end slavery in the 1920s. Of course, Brazil hadn’t fought a war to preserve slavery nor made emancipation illegal in their Constitution, so the 1920s is probably optimistic for an end to Confederate slavery.
The Brazilian government was overthrown when it ended slavery. The Confederate government was founded on the idea that any state can leave at any time for any reason. At a minimum, this will result in more reactionary states leaving the Confederacy.
Brazil will become an ally as will the Boer Republics so long as it does not interfere with the UK.
What do Brazil and the Boers gain from this?
US naval power will be expanded while the Confederacy will focus on submarines as much as surface craft.
The Hunley killed a lot more Confederates than Unionists.
]I figure the US and CSA have a good war left between them but not sure as to when it will happen.
The Confederacy is unlikely to survive a second war with the Union. Either side could have a real or imagined cause at any point after the signing of the peace.
The US will experience a great deal of immigration but I think the South will see a lot of population increase by natural means, and the South will be more religiously inclined than the North for better or worse.
Natural population increase in the Union would be comparable to the Confederacy. Immigration heavily favors the Union.. Better economic opportunities will lead to many southerners, particularly pro-Union ones, emigrating to the US.
The Confederacy will probably be more religiously conservative than the Union. Nothing but Confederate mythology indicates they were more religiously inclined.
By the 20th century I see a South coming into its own with the oil industry booming and cheap labor allowing for faster industrialization by Northern automakers who are not willing to risk union labor riots, allowing states like Arkansas, Mississippi, and Kentucky to build a respective industrial base of their own.
Kentucky was never part of the Confederacy and in 1860 had a better industrial base than the 2nd and 3rd most industrialized states of the CSA. By the time the oil boom hits, there’s a good chance Arkansas and Texas aren’t Confederate any more.
In period, cheap labor went where the factories were.. Union manufacturers will not be moving factories to the Confederacy, they’ll be using cheap southern labor as scabs in Detroit, Chicago, and Pittsburgh.
Overall the standard of living might not be as high as the north but it is much better than most of the rest of the world.
If we only look at the white population of the Confederacy, that’s probably true until the boll weevil hits. If anything resembling the Depression occurs, they’re in real trouble. A Confederate government is going to be less inclined to attempt job-creation programs than the Hoover administration.
Using World War I as a cutoff point, if only because I'm not sure what the 20th century would look like and whether a full war would be brought to North America, I see a Confederacy of 16-20 states (Cuba and three to seven others in Latin America) with electrification moving throughout the country if only slowly and automobiles starting to appear as they do in the US.
At independent Confederacy will be lucky have still have 11 at the end of the ACW. (At the least, Virginia, Arkansas, and Tennessee will be smaller than at the start of the war, likely also Louisiana and Mississippi. Foreign ventures are more likely to result in loss of Confederate territory than the gain of new states. And every political, military, or economic issue risks the Confederacy losing states.
By 1914 the putative Confederacy could be down to Alabama (minus the pro-Union northern counties, Georgia (also minus the pro-Union northern counties), and Florida (minus the parts taken by the Spanish when the Confederacy tried to invade Cuba.) Best case, they’ve also got Mississippi (minus the Union controlled counties near the Mississippi River) and South Carolina (after unsuccessfully attempting to go it as an independent state).and maybe an rebellion-plagued territory or two (not state) in the Caribbean or Central America.
Education is more difficult to obtain for the poor but not impossible if the parents are willing to help with it.
The spirit is willing, but the pocketbook is weak. Most white Confederates will get no more than a grade school education. Many won't get that much.
Industrial output is at 5th-8th place globally behind the the UK, US, Germany, France, and perhaps Italy or Russia. While not entirely self-sufficient the CSA does well enough for itself.
How does it achieve this?
Mississippi is becoming a banking haven as is Florida due to their very Libertarian laws, which are drawing international wealth seeking to avoid taxes from elsewhere.
In OTL the Confederacy dictated wage and prices. They forced railroads to carry government cargoes at a loss and ships to carry government cargoes for free. They drafted workers to prevent strikes and force businesses to complete government contracts. By 1863 there were more bureaucrats in Richmond than in Washington. The Confederate government funded itself by massive deficit spending and runaway inflation. They confiscated civilian firearms, instituted internal passports, and tried to institute Prohibition.
Which of those would a Libertarian support?
CSA submarines are as advanced as anyone else's in the world and perhaps as good as German technology in the early 1920s due to increased emphasis on research.
By 1914 the Confederates should be able to build submarines better at killing the enemy than their own forces, but they would lack the industrial and engineering base to be cutting edge.
Otherwise there are variables and it is not a perfect world but a victorious CSA is not floundering as some would think.
How do they pay off $2.7 billion in public debt with yearly government revenues of $65 million? How do they get a stable currency? What do they do about the 10% of their white draft-age men being in the Union army? How do they deal with the pro-Union guerrillas? What do they do about 1/7th of their slaves having run away?