Here's one thing to consider: How will things start out, initially? I can't find any estimates for 1783, but here's the 1790 census at the bottom of the post. I cut out all the breakdown of population.
Even at this point, Georgia would be wholly dependent upon South Carolina. They don't have the population early on that would be suitable. I doubt North Carolina would be able to hold onto Tennessee, but it'd be about as hard for Virginia to do the same with Kentucky et al. A lot of turbulence would be seeing if those states could keep their outlet to the west.
A note: I doubt that North Carolina would like to be put back under South Carolina once again (that was the whole reason the colony was split in the first place) especially as they are almost at the point where they are twice as large and half of their population are not slaves. Power would shift north to Charlotte, at least until/if Atlanta and Georgia proper starts to become larger and more populous. Talk about the tail wagging the dog in such a situation for South Carolina.
If we assume, then, that Virgina and South Carolina-Georgia manage to hold onto their western possessions, I imagine North Carolina/Tennessee/Franklin/etc would become the neutral state separating the two. That would be uncomfortable of the state, as it wouldn't want to go either way and be subsumed into the larger entity.
Of the northern states, I would have to agree, with one caveat: If Virginia is strong enough to maintain the west, wouldn't they also be able to contest Delaware as well? Pennsylvania might look towards New Jersey and pry it from New York if a strong Virginia looks to be able to contest the east.
Although, if Virginia and Pennsylvania are bartering in the East, would Virginia try to bully Delaware to give up a bit of the north to Pennsylvania in return for some of Maryland, who in turn would get the southern tip of the Delmarva, and Virginia gets a slightly more favorable claim in the west. Pennsylvania gets their access to the sea, everyone keeps the sameish amount of territory, and Delaware loses Bessarabia to get Dobrugea to make Virginia's tsar happy. ...First analogy I could think of.
1790 Census
Virginia 747,610
Pennsylvania 434,373
North Carolina 393,751
Massachusetts 378,787
New York 340,120
Maryland 319,728
South Carolina 249,073
Connecticut 237,946
New Jersey 184,139
New Hampshire 141,885
Maine 96,540
Vermont 85,539
Georgia 82,548
Kentucky 73,677
Rhode Island 68,825
Delaware 59,094
[c]
Total 3,893,635