The core has to be the most important part of the body to train if you want to make progress right? My thinking, if I (or you) were able to get on the floor daily or a few times a week and just start trying to turn side to side and strengthen those muscles what other exercise and functional movements could that lead to?
Would the turning side to side be the first thing to focus on? And what would be the next step or movement to work on to build on to that function?
If I sit all day in a wheelchair mainly in one position it seems like anytime I can get out and at least try to move in another way that it will be good for me. I may not even make progress in the first day or week, but if I tried something even though it might not be easy for a month, I know there would be improvements.