I was in a bad car wreck & sustained some bad injuries - died three times in the helicopter, in hospital several weeks, several surgeries, wheelchair for 2 months then crutches then cane. Drs. said I probably wouldn't walk right again but I am slowly getting rid of my limp

Running is out of the question as of now.
My question has to do with my legs. I have been using my home gym for upper body ever since I have been able & before that I used 20 lb dumbbells in my bed. I had a compound fracture in my right leg & had to have a rod put in running from my knee to my ankle & had to regrow 3 inches of bone to connect the halves together (narrowly avoided a bone graft with tons of milk & caltrate pills)
In therapy they had me ride a stationary bike slowly and put my foot on a disk with a ball on the bottom center. I would then rotate the disc in a circle at an angle so that the edge touched the floor as it went around to get range of motion back. As I improved a larger ball was put on to increase the distance my ankle had to flex. I have the range of motion back in my ankle & no more therapy is covered so it's up to me now.
I have lost a lot of size & strength in my legs & was wondering what exercises would be recommended as best for someone in my situation. I just started doing squats with no weight & my back against a wall. Do you think I would be better off going to a gym & doing light angled or horizontal leg presses or just stick with the wall squats? Would light leg curls or stiff leg deadlifts be better for hamstrings as of now? Would there be any benefit to doing lots of leg extensions with no weight (I can't take the pressure of any weight on the front of my leg yet) or should I wait till I can use some weight for them? For calves I just started doing raises on the bottom of my staircase & stabilizing myself with the rail.
This has been a long & frustrating journey so far & any input is greatly appreciated...