We rented one in 1995 down the Grand. We hooked a 10 hp Honda short shaft to it and ran it mostly in the flats, it did little to help in rapids. We had 6 kayakers and 2 on the boat, sometimes 3 on the boat with an extra kayak. Space was not an issue. We had plenty of food, ice, and beer. Could have hauled more. I rowed about 95% of the rapids, I was 16. We got hung up pretty bad twice, but we never came close to flipping. I'd rock another one, but with a larger motor and long shaft.
Wishing I was on the river instead of surfing the web...