UPDATE: Went to my LBS today (
Metropolis Bikes in North Hollywood CA) and they only had one Dahon in the store (the Mariner, I think) - the guy there explained they had sold all the other ones and weren't ordering any more till after some bike show in September in Las Vegas that they're going to.
Anyway, he let me ride it and I liked it! I think the fact that I'd already done that breathtakingly exciting run to the Post Office this morning made me feel more confident. Then as if that wasn't enough, he encouraged me to test-drive an electric bike called the "Pedego" - fun! (WAY more than I could ever spend, of course, but fun nonetheless!)
Anyway, I'm glad I rode the Dahon because now I have a better idea what they feel like. Does seem to be a well-built little bike. Who knows, maybe I'll wind up getting something like that instead!