Hi Howie,
I am sure someone will weigh in with a more thorough packing list. But I did want to weigh in on pants. Your leg is going to be very stiff and probably somewhat swollen. I have to be honest, regular loose fitting clothing is a real non-starter. My thigh was quite traumatized. There is no other way to put it.
Driving in warm-ish weather I would go with loose fitting, plush basketball type shorts. You know the type that go to your knee. Or I'd cut pajama bottoms off at the knee. Then I'd just have a light blanket handy to throw over your legs as needed for warmth/comfort.
You could do sweatpants but you would need help getting them off and on, and they would have to be pretty loose, particularly up high, nearer the waist. Frankly in the first 3-4 days you are gonna need help with getting on any clothing. Even at three or four weeks socks are going to be an adventure.
For footwear you want something that you can slip on and off with just your feet, but that will also stay on on their own (ie open backed slippers are gonna be falling off all the time. Something like a slipper moccasin would be ideal.
You are probably gonna be hooked up with a kit of tools by your doctor, but you are gonna need a reacher, a leg puller, and a sock puller. You won't be up for using the sock-puller until after you are home, though.
Car trip is gonna be uncomfortable, but make yourself some ice-bags. How long is the trip?
Mike