is the river deep enough for a small motorboat, and is their a boat ramp on/nearby the camp to back a boat up (on a trailer) into the water?

Not at the campground, but there are other river access points. The river is fast moving though and there are a lot of underwater hazards.

Not at the campground. But there are places nearby.

No....but there are a couple of lakes near by the have boat ramps and great boating/fishing...