I've had a few. Had each ACL done and the left one tore again after 5 months. That was probably my fault for trying to get back on it too soon and not let it heal as well as the first one. I did a lot of physical therapy on the first ACL reconstruction and it is still there. As far as walking, that depends on you. They told me at rehab to put weight on it as soon as I could. Of course, that doesn't mean full weight on it right away. They meant to put as much weight on it as possible while still using crutches. Expect to be awefully stiff after driving any long distance if it's right after you are able to walk.
I was cleared to do whatever I wanted after 4.5 months on the first surgery, but I was 21 and worked very hard to get back to normal. I'd suggest getting used to pain and taking rehab seriously. The most pain I notice from it now is where they took the patella graft from. Other than that, the ACL doesn't bother me. It's the multiple scopes and repairs of cartilage that gives me a nice ache once in awhile. If you are like me, you won't be able to sit still even though it doesn't feel too good to move after a couple of days. If you have any questions feel free to PM me. Unfortunately I have had 5 knee surgeries and have a little experience with them.