I'm going to second the idea of strength training. One gentle way to get into it is through rubber bands. After a couple of months of investigating the various companies that sell these bands, I began ST with a starter set from Rubberbanditz. Their bands are long-lasting, their video is full of creative ideas for using the bands in whatever situation you find yourself, their beginner program is easy enough to get you going, and they donate to + work in third-world countries.
I'm very glad for your medical clearance and wish you the best, whatever you decide to do.
The Beck Deck Crew!