If you have trouble walking, at least stand. For a long time every day. I saw patients with pain and stiffness and other mobility issues, and they stopped even doing that. They just lay in bed getting depressed after a while. So mental toughness is important.
I don't know what a laptop stool is. I always used a tray table, the kind usually used for eating in bed; I'd eat breakfast, wipe it off, then my laptop would go on it. And you can put the legs of your wheelchair up, put your pillow(s) on top of them, and then put the tray table on top of the pillows in order to sit in your wheelchair with raised, straight legs. It's good to alternate between bent and straight legs frequently.
A bamboo back scratcher. Not necessarily for scratching anything, but they're great for grabbing or touching things that are just barely out of reach, like light switches or drawer handles. Sometimes small movements are a lot of work and pain.
Sleep is your friend and pain is the enemy of sleep. Bring some sleeping pills in case you're going to a doctor that doesn't prescribe them.
Clothing appropriate for the weather not just when you arrive but when you're scheduled to leave in case you have a hard time finding any. Not sure where you're going and whether it's far from home or not. Beijing got surprisingly cold toward the end.