This is a very easy paddle in slow moving water mixed with large sections of river that open up to lake size areas.
The river heads west from Plymouth Beach where the Eel river empties. If you head upstream, you can travel about 1.4 miles until the river becomes too shallow and overgrown with vegetation to continue. Up until that point the river meanders through slow moving sections and some large bodies of water. The river passes under exit 4 (Pilgrim's Highway) and also under River St. The River Street bridge is very low and you will need to duck to get under it. You may also choose to portage over, it is a single lane road with almost no traffic.
The river passes by Plymouth Plantation and many houses that are situated near the banks. I would rate this as a very easy paddle through mostly narrow and shallow, slow moving water.
No facilities, no dock or any other landmark. Simply put in at the river edge.
You may need to park at Plymouth Beach and portage across the road to put in; there may be a fee to park at the beach.
Take Rt. 3A to Plymouth Beach. Across from the main entrance to the beach are some old fishing shacks. Walk between the shacks and to the right is the river.