With a single boat I've towed it with my four cylinder, GMC Canyon as far as Omaha. It was a little sketchy, and 5th gear was rarely used. Not enough power, suspension, or brakes to really call it safe.

The ultimate plan is to build a sort of collapse-able camper that'll nest under the back boat. Just flip the panels up, toss the roof on, and have a dry 8x8 place to sleep at regatta's. Gotta scrape up the funds for my monster sail box first though.