Start exercising your knees now. If you can, talk to whomever will be doing your physical therapy and get them to recommend some exercises you can do now; even just a few weeks will make a difference.
And definitely do them after the surgery. Our school crossing guard had to have his knee surgery redone 3 times because he would not do the exercising. His doctor told him before the 3rd surgery he would not do it again, that he (the guard) had to make the commitment to do his part!
I also went around the house and made sure that throw rugs and anything like electrical cords, etc., that might possibly be a tripping hazard were removed. Look at small stools and other pieces of furniture that might also trip you up. Bending over was hard at first and so, with the second surgery, I knew to move certain items up higher such as toilet paper, cat food, and other items on low shelves.
Make dinners ahead and freeze them so that standing in the kitchen cooking is not needed. Make lists and grocery shop as much as possible ahead of time. I wanted my time spent in rehabbing my knees and not being worried about the every day "stuff".
I loved walking up and down my driveway as part of my exercising so I made arrangements with a neighborhood kid to sweep and /or blow off my driveway every day as my neighbor has 2 giant oak trees and I didn't want to trip over leaves and acorns (had my knees done in the fall).
Check placement of phones and remotes so that they will be in easy reach when you are sitting.
Gather a bunch of hand projects you can do until you can get back to your sewing machines. And don't forget all those books you've been meaning to read.
I know that that may sound counter-productive to getting up and walking but you will be doing a lot of sitting in between exercise periods and nothing was more frustrating than sitting down after doing my exercising and then having to get back up to get something.
I love having had my knees done, almost 7 years ago now. My older brother and sister both tried to talk me out of it saying that I would have to have them done again if I didn't wait until I was older. My reply was that if I didn't get them done "now", I might not make it until "older" and that my knees hurt so bad that even if I had to have them redone after 10-20 years, it would be worth it. Within 3 years of having mine done, they both had theirs done and admitted that they couldn't believe how much relief it was to them.
Good luck and let us know how you do when you can!