It'll be tough on a 185 Cruiser, I think...
Mine's only a 4 speed, though... that might be a problem for me. I'll probably have to change ratios to get higher than the OEM rated ~65 (I think that's the right number) without employing serious HyperMiling tactics.
First things first, maybe getting a test ride in, and even if not, I'm going to go over it completely, clean it up, and get it running in perfect form. Then I'll worry about playing with it.
Of course, I'll establish a base-line mileage before I even bother making any changes, but I do want to keep it able to be returned to OEM as easily as possible. I'd actually love to keep it all OEM optioned, if I could. We'll see!