I’ve been using a Garmin GPS Map 76CS plus for two or three years now. It’s a marine unit, floats, color screen, and auto routing(with the additional road maps downloaded). I use it in my truck and on the rivers.
I’ll agree that the whole map buying, limited unlocking, and multiple formats for maps really suck.
At the same time, garmin units are the most versatile, user friendly, and feature rich gps units around.
Drifter, the key to running rivers is to make your routes at home. Then your river routes will be point to point, straight lines down the river. So your mileage will be close, as well as ETA readouts.