I have made a few trips in late summer in 2011 and covered about 14 miles of the river from Egg Rock to Lawrence Street using my WildSystem Pamlico 120. As usual, I publish my report here and hope my journey can provide some helpful suggestions when you plan your trip.
Good access point for kayak:
From upstream to downstream, using Latitude and Longitude
1. Eggrock (Concord) to Rt 225 (Bedford)
The river condition is good, can't feel the current. For the 1st half of trip, I would suggest you dock your kayak in the Old North Bridge to visit the Old Manse and the Minuteman Statue. Another stop is the Great Meadows on your east.
The 2nd half of trip, you will experience the widest (150 yards), longest (3 miles) and straightest part of Concord river.
2. Rt 225 Bedford to Faulkner St Dam Billerica
The 1st half of river is at least 100 yards wide and not many residential houses visible due to the Great meadows on right. The 2nd half (downstream of the river street) of river is about 50 yards at most of places and current picks up. Near the end of trip (after Pollard Street), it is literally water rafting with big rocks visible underneath and return trip almost impossible. I don't suggest beginners to go further downstream after Pollard St if you still want to come back from the river. However, if you manage go past that, be careful! Faulner St Dam is ahead of you. Be Alert: The obvious red brick building with bell tower on the top and the loud noise of fall
3. Billerica Fire Station on Lowell St to Lawrence Street Bridge, Lowell
This is a short trip only about 2.5 miles, with many tall silver maple trees on both sides blocking whatever behind them. The most parts of river about 80-100 yards wide, easy to paddle through with slow current noticeable when going back. The big rocks in the middle of river often become the favorite rest spots for double crested cormorants.
4. From Lawrence Street Lowell to Merrimack river Lowell
I wonder if anyone ever kayak here, very dangerous for kayaking.