I would try to take in Niagara Falls along the way. You could cross into Canada there and travel through Ontario into Quebec. Stop in Quebec City and tour the city & Montmorency Falls. In New Brunswick make sure you visit Hopewell Rocks. You can take in Fundy Trail Parkway, Magnetic Hill and the Reversing Falls. Nova Scotia you will want to visit the Town of Lunenburg, Peggy's Cove and make sure you tour the Cabot Trail. You could then travel home a more direct route through the US. Travelling through Canada will add a few miles to your trip but will give you an alternate route so you don't have to backtrack.
If you travel in the summer make sure you plan ahead and make reservations.
