It is so hard to know how you will be doing so soon after the TKR. I would say to reschedule, based up my experience with DD's TKR.
DD had a TKR in Sept, she is 19 years old. (LONG story, she will have the other knee done in March). OK, this may not be typical, but at 6-7 weeks post-surgery, she had to go in for a "manipulation" under anesthesia. They put you to sleep for 10 minutes, and bend your knee, to break thru the scar tissue inside). Set her back a little more, but now at 9 weeks post op, she is doing fairly well. At 6-7 weeks, before the manipulation, she was only at 80-90 degrees, tops, and a WDW trip would have been almost impossible. As they will explain, the problem is not the new knee, it is the muscles, tendons, etc.
While she was driving about 2 1/2-3 weeks post op, she has not returned to work (PT retail job, on her feet all the time).
Good luck what ever you decide!