Steve:
OK, I hear ya now. Hyde Park doesn't really have great EL (CTA) access. It has some Metra stops though. However, most people take the Jefferies Express bus to get downtown. That bus has a bike rack on the front so you're golden whatever you do.
As for riding up the lakefront that is the real deal. Not much in the way of hills at all but what we do have is plenty of wind. I've taken my Curve down there a few times. In spring when the wind is really whipping it can be fun going in 1 direction and impossible heading back.
My 3 speed curve wasn't too much fun riding against the wind last May. I kept her in the lowest gear and I was still beat. That said, I've also done this punishment with my 18 speed mountain bike and it still ends up being really hard.
The good thing is that you'd be using it for recreation and not transportation which makes a folder a good snivel option (meaning if the ride is painful you jump on the bus and take the bike partway).
I think you should test ride a few options at those locations and buy whatever you think is bichen'!