The 1000 Islands Parkway is the slow road east from Gananoque toward Brockville. It was once part of the main highway, but now works better as a river drive, cycling route, and place to pull off for St. Lawrence views.
It is not a single sight so much as a way to stretch the day. Bring a bike if the weather is good; the old road alignment makes the river feel much closer than the inland freeway does.