This really is a small world - I'm in MD, not too far outside D.C.

In my opinion, I wouldn't disclose about your MS in the interview. Especially not to try and get an advantage in the job search. More likely, your disclosure would have the opposite effect. And once it's out there, you can't take it back. A few weeks ago, I had a beer with some former co-workers; I like to keep in touch in case I ever wanted to go back to work there. Well, I let them know I have MS, and now I'm kicking myself. I wish I could take it back.

I can't add much about the physical - I've never had a job that required one. One other thing you might want to consider though: whatever health insurance you have now, try not to let it lapse (easier said than done, I know). I believe the way the laws are written, if you get on a group policy, there is no exclusionary period for pre-existing conditions, as long as you don't have a lapse in coverage. Individual policies - that's a different story.