I know it's not a Brompton or Birdy, but Sunwest Cycles in Palm Harbor carries Dahon bikes. It will at least give you feel for a folding bike. Who knows, you might even find one there that you like.

As for the Brompton vs. Birdy thing... In your case I would probably go with the Birdy for its versatility, especially since you'll be storing it in your car between rides. If you were in a city and doing a lot of bike--train--bike during rush hour, I would choose the Brompton for the faster and smaller fold.

--sam