I've seen boats like this before, they work fine with trolling motors. I'm just posting this link as an example of the style of boat, I don't know what they're called.

http://www.basspro.com/webapp/wcs/stores...SSELL_THUMBNAIL

I think that a paddleboat is still a good idea, they're easy for novices to figure out. Trolling motors get broken when kids use them, and canoes require experience.