I have done a little with the weight machines at the gym since my surgery (which was about a month after yours). I keep intending to do more!
Right now I have been mainly focusing on the machines which are cardio for most people I guess; the stationary bike, the seated elliptical, and the Nustep crosstrainer. Since my leg muscles were so weak after surgery, these have been helping my leg strength as well as cardio.
If it gets to the point where my legs are strong enough that they are no longer increasing in strength with these cardio machines, then I'll spend less of my gym time with the cardio machines and more with the weight machines I suppose. So much of weight lifting (in general, whether machines or free weights) seems to focus perhaps more on the upper body, but there are weight machines that exercise the legs and knees and can be set to very low weights to begin with. And then, my upper body could use some strength workouts too. I do lift heavy things around the house now so there's that.
I've never tried the resistance bands, although I know they are inexpensive. I guess I feel like the weight machines are a more controlled and predictable lift. I have 1, 2, and 3 pound dumbbells but I can't figure out how to get much benefit from them for my legs. My legs are still too weak to use the strap on ankle weights quite yet.
How about climbing stairs? I have noticed that really is quite a workout for me these days.
I climbed up a flight of stairs briskly last Saturday and it took me two days before I felt human again.
OK it was to the second floor of my gym, which has 20-30 foot ceilings on the first floor, so that's my excuse. I plan to try that again in a few days.
I love that after all we went through, we are now talking about our plans to increase workouts and strength!!