Ed,
I had my right knee replaced 18 months ago. As others have said, stay ahead of the pain, especially that first couple of weeks. I had some home therapy and nursing, along with several months of physical therapy 3 times a week.
Had the other knee replaced 6 months ago. No home therapy, less than two months PT. The one thing to do is just get up and move, walk, exercise. Not to the extreme, but just build up how much you walk about daily. My surgeon was extremely pleased with my progress, so much so that as mentioned above, it reduced the physical therapy time. Key is just build up the strength, the rest more or less takes care of itself. With time, more flex, more strength....
Good luck with your recovery!
Gary