We had 55hp Mercs on our Zodiac F-470 boats and that was way more power than what was needed. As GW mentioned, they are easily folded up and put into \"bags\" that can be put in the back of a small pickup and hauled away. The only bulky part is the hard floors if you choose that option, the motor of course (55hp is a 2 person carry), and fuel tank(s).
Another option if you don\'t want to haul the boat away during a multi-day excursion is the submersible 35hp motors (although much more pricey). You would also need CO2 bottles for this. In short, you cruise up to the beach, unload your camping gear or whatever, then take the boat back out and deflate and sink it (with a couple hundred pounds of lead or similar weights on board). The boat, motor, fuel bladders, everything sinks and you retrieve it later. We only did this method with scuba gear, so FYI. That was the military method, maybe too gung-ho for most people.... Also, since this setup would be privately owned and not Uncle Sugar\'s property, you might want to think about tide and current shifts. Would hate to see your boat swept away under the surface.
Chris