Good luck on your TKR. Below are my thoughts... Most here will echo them:
1) Don't expect to get back to normal in a few weeks. Most say after TKR it takes about a year before you wake up and don't immediately remember you had TKR. That doesn't mean you won't be functional, but it will not feel normal for a long time. I'm 1.5 years out, but I also had a tendon issue and a second surgery. It still does not feel perfect, but it is functional and there is no pain.
2) Be prepared. Have elevation pillows, cold packs or ice. Toilet riser (trust me this helps), walker, etc. Get all that stuff ahead of time. As mentioned above putting on socks and shoes a pain. Get a sock helper or if you have someone to help, then that is great.
3) Do not over do it on motion, bike, walking no matter what your PT says. Go at your own pace based on the comfort of your knee. I tried to push it and definitely, you pay the price.
4) The biggest fear with TKR is falling. Most people that fall with a TKR do some kind of damage. Some, like myself, require another surgery and a long healing. So do anything and everything to avoid any kind of fall.
5) A stationary bike is essential. It is actually a better exercise for your new knee than walking. My physician sent home instructions to ride the bike rather than walk whenever possible. At first you will not be able to make full circles so rock gently back and forth. When you can make full circles it will come as a great, low-impact motion for your knee and it will help with blood flow, healing, and comfort.
Lastly, and most of all, be patient. You will have good and bad days and periods. Just get through them. Time is your friend and over time you will heal and things will get better. Sleeping is also very difficult after TKR. So plan to have pillows you an prop up on and try various things to get comfortable. But sleep will get better.
After my tendon operation on the same knee as the TKR, I struggled to sleep for a month. Then one night I managed about 5 hours and it felt sublime! After that it just slowly got better and better. So when you cannot sleep have something near by you like to do. For me, as a software developer I had my laptop near by and I would either write software or when not feeling it, I would just watch movies or TV shows over streaming. Finding a way to distract you from your discomfort is important.
Anyway good luck!