My wife and I took a meandering paddle down a portion of the Contocook River. We put in at a riverside stop on route 136 heading towards Greenfield. The put in is just on the left-hand side of the road just after the intersection of 202/136. The actual canoe put in on route 202 near this intersection was un-usable due to a large amount of debris and log jams present at the put in site. The put in we used was just below this log jam.
The trip was very pleasant, though the water level was very low, we were still able to paddle almost the entire way, while scraping the bottom of the canoes once or twice and also having to portage around another log jam about 2 hours down the river. The trip is about 7 miles in distance and it took us about 3.5 hour with a couple of rest stops and lunch.
The river itself is very nice. You will need some knowledge of river navigation in order to do this trip in low water. You will need to be able to find you way around boulder and choose the best routes to stay in the deeper water. We ended at the Powder Mill Pond NH Fish and Game launch. This end can be gotten to by following 202 north towards Hancock and making a right turn to head towards Powder Mill Pond. It is clearly marked on 202 and the entrance to the pond area can be found just after the covered bridge. You may also bypass the power mill take out and continue onto Powder Mill Pond which is another nice paddle.
Any branch you choose on the river will surely lead you in the right direction, most V's in the river just go around large islands. We did have to navigate a number of downed trees and such, but was manageable in our kayaks. Would not recommend this in a canoe unless the water was considerably higher.
Porta potties at Powder Mill Pond
Put in located on route 136 towards Greenfield just after the 202 north intersection. Powder mill pond can be found off of route 202 north heading towards Greenfield also.