I've collected some opinions now, and made two orders, with at least one strange result.

My phys therapist recommended a foam donut. I ordered one, and it was ridiculous---an itsy bitsy piece of nothing that couldn't possibly absorb any shock. I've sent it back. A doctor recommended gel, and I found a gel seat that looks like it has some support, so I've ordered it:

http://www.autobarn.net/gel-seat-cushion.html

It hasn't arrived yet, so I don't know.

Today I saw my feldenkrais person. She thought the gel was all wrong, as it absorbs vibration but not shocks (who knew?) and suggests hard foam. Too late. Also, she says stay away from tempurpedic, as I dont' want something that will collapse, but rather something that will retain its shape.

I've looked at kmeb's idea, and it looks good, but late. I need to have whatever I'm committed to by Tuesday.

I ordered the magnets, but they haven't arrived yet.

Today I bought lots of blister products, just in case; had feldenkrais, as not only is my neck hurting, there's a suspicous feeling at the bottom of a foot, and still, the butt. She did help the foot.

I'm packing light on clothes and heavy on health aides!