I have been down a few rivers with my 2010 outback. As mentioned before, the outback will ground in the shallows slightly sooner than most kayaks, but other than that it handles well.
I do not install the drive in most river paddles. However, I tie about a 4.5 foot rope to the drive and clamp it to the bow fixture (you don't want to have the thing go overboard and not be able to retrieve it), then I secure the drive, wedging it fin-first pointing to the front, into a small foot-long bungie cord that I string across the bow hatch cover. That way the drive is secured to the bow, yet it is handy to grab and install when my shallow river suddenly becomes deeper backwater, such as behind a dam.
Absolute kayaking corrupts absolutely.