Took the private boat tour and totally enjoyed it.
We got picked up by private minivan from our hotel and taken to the boat dock. The boat is very nice, it can fit 5 or 6 people confortably I believe.
Boat time is 2 hours, you go through the locks and see all the main sights approx. from Visherad up to the lower lock and back, at the end they drive you back.
The boat captain ( or should i say skipper ? :-) was really nice and funny, and he made the trip much more enjoyable.
Much better than getting on one of those big boats in my opinion.
He points out the main sights for you and answers any question you might have.
Some nice music playing in the background, the breeze of the river on your face, the sun warming you up....definety recommend this, especially after a morning of walking to the main sights you will enjoy the relaxation of the boat tour even more.