I had a TKR (knee) in January, and my knee is way better than before. I was up on Mt Whitney in June, and the knee did well. My surgeon was a bit surprised that I went so soon.
Now, the other weaknesses in my bones are showing up -- arthritic ankle. But the knee seems to be as strong as the other one.
You should do everything you want up to whatever limits your doctor places on you.
Oh... one more thing: buy the lightest equipment you can find!