We've been there, a few years ago, with the kids. Pleasant. Not much in terms of suggestion...
I remember taking the Confederation bridge (shuttle, not allowed to ride), visiting a site dedicated to Ann of the Green Gables, a must see for some and a pass for others, regretting not having knobby tires that would have enabled us to ride charming backcountry roads covered by a rather thick layer of red dust (2" Supremes were spinning), and being underwhelmed by the campgrounds at a couple of National Parks, a few yards from the sea, but with little to no privacy. Most people loved it though.
From Vermont.... The Route Verte had a nice corridor up to Quebec city, then north east up to Rivière du Loup, then New Brunswick (mostly on paths), then Nova Scotia. Our bunch started close to Portland (ME), then New Brunswick. Great memories from Maine. Perhaps less so from New Brunswick where the are few accommodations so you have to get used to gas station gastronomy.
