Hey, I was also diagnosed with pre collapse AVN in my right hip. Got two opinions and both recommended either medicine (fosamax) or decompression. Because I'm only 28 with no collapse they really weren't prepared to replace it. I did some thinking as well as some reading and I finally decided that I was going to have the core decompression, no graft just the decompression itself.
I just had mine last Friday and to be honest it really isn't that bad. My pain was never that bad to begin with before the surgery, it was more of an annoyance but I knew that I had to do something about it or else I risked a collapse. I'd say the worst part so far is just the muscular soreness around the incision that is rough, so I've been stretching it out trying to get some mobility back and it's been working. I'm sure most doctors will tell you that you'll need crutches for 4-6 weeks which is what I've heard from both as well.
Seems like the hardest part is remembering to not put pressure on it, because I honestly have minimal pain at the femoral head itself so I can stand without crutches but i know for the best case healing I need to stay off it.
If you have any other questions feel free to let me know, good luck.