One piece suits are actually cut so that they fit best, when in a sportbike crouch. Two piece suits can either be for racing, or for touring (mostly the former). For example Aerostich has a new leather touring suit, that's impregnated with Goretex for weather protection.
http://www.aerostich.com/transit-two-piece-suit.html
Something like that looks perfect for the cruiser route. I'm just not sure about the protection pads, the description doesn't really say much about them.