Canoeing- I assume you are interested in flat water rivers and lakes, not whitewater so:
Umbagog Lake is a wilderness lake located in Coös County, New Hampshire, and Oxford County, Maine. It is one of the most pristine lakes in the state of New Hampshire. It lies in the towns of Errol, New Hampshire, and Upton, Maine, as well as the townships of Cambridge, New Hampshire, and Magalloway Plantation, Maine.Wikipedia
Saco River in NH & Maine, has both flat and white water. Guide books available as well as outfitters running shuttles.
Be advised that on weekends during the fall foliage season the "leaf peepers" create traffic jams in the mountains and many camping spots are full.
Many, many years ago we would purchase a road pass to drive on the private logging roads in Northern Maine along the Pennobscott River, camping, fishing and canoeing. Don't know if you can still do that, but logging trucks have the right of way and they do not slow down.
Algonquin Provincial Park, north of Toronto, west of Ottawa is beautiful, if you are taking the route thru Canada, great canoeing and camping.
You didn't mention National Parks, but I highly recommend Arcadia National Park near Bangor, Me, lots of easy hikes, beautiful coast and GREAT lobster. Less crowded after Labor Day.
I lived in NH and played in VT, NH and Maine for over 25 years, but haven't been back for 20 years, so things may have changed regarding access and crowds, but Northern VT and Northern NH are less crowded than the southern ends. Maine away from the coast and north is less crowded. Of course once the kids go back to school mid week the crowds slack off.
Have fun planning, lots to se and do, you will burn up 60 days rather quickly.
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