Hi Sacred!

I do traditional exercise as well as Pilates. I don't know if you've looked into it already, but Pilates is a fairly slow, generally mat-based workout which strengthens and stretches muscles.

I don't know if it would be easier for you to follow than yoga, though.

I like Don's suggestion for anti-dog tactics, especially since I think walking is a great, relatively gentle method of getting in shape. But I totally understand why you'd be hesitant about walking in your situation. Sounds scary!

Indoor cycling might be good, too, if you have access to it, because it supports most of the body weight on the seat. But I don't know how your joints would like it.

Sorry I can't think of anything else right now. Wish I could help more.