Instead of towing a line of boats behind a single powered boat, why not yoke two or three boats side by side? Your towing vessel would be a temporary trimaran. Behind that you could pull another trimaran or catamaran.

You'll get better stability and more leg room in the tow boat, as you can keep the cooler in one of the side boats, and stilll have it within reach of the group riding in the center. The side boats are also good spots for naps, or places to banish the worst punster.

The boats can be easily unyoked for solo paddling, or you can add a sail to any configuration: single-, double-, or triple-hull.

Check restrictions at Boundary Waters area. Most of the lakes there do not allow motors--not even electric ones. Some forbid sails, too. The bigger lakes where motors are allowed can be choppy on windy days. The added stability of linked, multiple hulls might be appreciated, even when paddling.

Enjoyyour trip.

PGJ