Seven weeks is plenty of time to heal from even an open procedure! I think you can lift items over 10 lbs. after 2-3 weeks. I was hiking 10 miles/day a month after my surgery. As I can recall, it was a long time ago, but I had my surgery on May 1 and I was working on Memorial Day weekend.
I also started chemo around that same time (a month after surgery).
So, YES you are being way too overprotective.
Let her do what she wants, she is fine at this point, and I am sure her doctors would say the same thing. She needs to go outside and take her walks, it will lift her spirits!