Walking is great. Several of my doctors have told me it's probably the single best exercise/activity we can do (assuming we can do it). I can't (much at all), so I'm trying Tai Chi w/ some Qigong mixed in. I'm also getting out a bit and working with my therapy dog. That's good for both of us.

One other thing that has helped me with both pain and weight is a diet for intractable pain (briefly, at least 50% protein, no carbs/sugar, no dairy except cheese, no fruit juice).
http://pain-topics.org/pdf/IntractablePainSurvival.pdf
(Page 34)

It's been 2 years since I've had any dairy, and in an evening of weakness last month, we broke down and got some ice cream from a local dairy. The next day my pain levels went up 2 points, I ached all over. A couple days later I was back to "normal" (for me). Curious about this, I repeated the experiment a couple more times, with the same result. Apparently dairy is a no-no for my particular metabolism, which is a shame, cuz I love the stuff.

I'll probably do it again from time to time, (even my doctors agree, "ya gotta live") but no more than a couple times a year. It might be worth it on a rare occasion, but not more than that. Gotta pay the piper.

Doc