At one point in time, the Russia (think Reds) were basically offered a cease fire in place. I don' think this is where the negotiations would start, but it is a likely ending place. So depending on the month, we are looking a the loss of Lithuania and Poland. If you wait long enough for the Tsar to fall, you may be looking at the loss of Finland. Now a talented negotiator might be able to get a even better deal, and get some of Poland back and keep gains in Armenia. For example, if the Russians offered a phased plan in early 1917 before the Tsar fell where there was an immediate cease-fire, and after the war, the Polish border would be the Bug River/Cuzon line, the German High command would be hard pressed to turn down. Now on Romania, the CP likely accept it with mostly its original borders. Bulgaria wanted the land lost a few years before and A-H wanted a little better line in the mountains. And the CP may not want a puppet, but they will want at least a neutral Romania. And I think the terms likely include the Ottomans regaining some of the lost land if the Germans are willing to haggle a little bit. For my TL, I don't have a good source on German attitudes towards helping the Ottomans in a win scenario, so this is a bit of guess work.
If you look at the B-L, it shows heavy war reparations are unlikely. The treating has huge terms about resuming trade, but little on reparations. Likely the Tsar/Whites could get terms that mere obligated the Russians to sell food and other critical materials to the Germans for the duration of the war, and a post war limit on tariffs.
Once you get into 1917, a revolution of some type is unavoidable. While the Reds take credit for the revolution with their Propaganda, the reality had more to do with food. By mid 1916, St Petersberg is getting less than 65% of the wartime ration. So from a pre-war diet of 3000 to 4500 calories per day, the city was probably near 1500 hundred (explanation would get a bit long on calculation). By the late winter the people had little to no fuel for heat and it was announced their would be no food at all for many days. For people with very low body fat due to a starvation diet, this is a near death sentence. Death by horse trampling or saber is better than dying on hunger in the cold. The people had nothing to lose. IMO, once you get past April 1, 1916, it is very hard to save the Tsar. You have to plant the crop to harvest the crop. And by the time the Brusilov offensive stalls, it is absolutely impossible to save the Tsar. And since the men/horse need to be out of the army and back at the farms by the May/June timeframe, you likely need a peace deal by early January 1916 to be sure you can save the Tsar. It is pretty easy to write a TL where peace is made in 1916 and Russia still falls into chaos in 1917. The Japanese/Russian war cause huge problems for the Tsar, and the Tsar did not have a defeat within 8 times zones of the capital. In distance, this is roughly the US Army losing a battle in Iraq and the USA falling into mass riots. Or the UK losing a battle in the Ganges River valley, and riots in England proper.