Thank you very much. My health problems are my dysfunctional digestive system, knee problems and depression, so I can't run/stand long periods, need to sleep a lot from medications, and have to closely monitor what I eat along with stress... the stress being a big issue. I wouldn't except to work with someone 24/7 but I would prefer to as it helps lower stress, therefore would make me more productive. I wish there was a way to help only certain days, but I guess that would undermine the position as being "staff". I'll probably just wait another year before trying to work.
However, I know one thing I could do is setup and breakdown of tables and such like in the dealer's room, though I wouldn't know who to even ask about that. It's not much, but I'd feel better knowing I was helping, even if only a little.
It sounds like your best bet would be volunteering, at least for now. Volunteers aren't staff and don't have a set number of hours to work. They are eligible for various rewards based on how many hours they spend volunteering.
Just request a volunteer spot where you wouldn't be required to run around a lot. Volunteers are often the ones checking badges at the dealer room door - I use volunteers to check badges at panel room doors too, for busy times, or when I'm low on staff.
Volunteering would allow you to work only when you wanted to work, and specify the days and times you'd be available. (Assuming volunteers were needed at those times.)
You wouldn't get much in the way of 'rewards' if you didn't work very many hours, but it'd be a way you could help and be in control of everything so that it wouldn't overwhelm you.
You mention helping set-up and take-down on dealers tables - are you planning to arrive at the con site on Thursday and stay through Monday late afternoon?