I've been posting here too much lately. One more, and then I'm on vacation.

The low gear is fine for the rolling terrain in my immediate area. There's always some kind of hill, but we aren't talking mountains here. Sorry if this is vague, but riders and terrain differ, and you may have steeper, longer hills to deal with than I do. The best I can tell you is that the 42 gear inches value that Dahon gives for the low gear is about right. If you can put any bike that you have now in a gear ratio that's close to that, it should give you an idea.

I put a Brooks B-67 saddle on mine, which does have springs. Even before that, the ride was pretty soft, probably because of the Big Apple tires. I wouldn't know what to recommend for a suspension seatpost, but you might find it doesn't need one.