You will find lots of suggestions by searching this forum for the provinces, and the other suggestions in your thread are good. We live near Ottawa Canada, and took the kids to the east coast most summers, either hoteling or tent camping. There are lots more places on my bucket list, but here's some highlights over our past travels in no particular order.
New Brunswick
The St John River valley is scenic.
Reversing falls in St John
Hopewell rocks
Fundy National Park
Bird sanctuary in Sackville
Ganong chocolate factory in St Stephen
PEI
Anne of green gables area
Lunch at the Blue Mussel in North Rustico
Red Point Provincial Park, Souris. A less busy area with "singing sands"
Just driving along the scenic byways with the red dirt, endless dark green fields of potatoes, and blue blue sea and sky.
Walking around historic Charlottetowne
Nova Scotia
Joggins fossil cliffs
Historic Halifax
Peggy's Cove. touristy, Swissair flight 111 memorial
Alexander Graham Bell museum, Sackville
Skyline walking trail Cape Breton highlands
Meat Cove mentioned above is very neat. Steep badly maintained roads, but a very interesting history (think Hatfield-McCoys) and beautiful views. My wife still wears her Meat Cove hoodie.
Newfoundland
Downtown St John's and Signal Hill. Steep hills!
Twillingate area is very scenic.
Gros Morne is on our bucket list.
Note that the province is deceptively big. It takes a long time to drive places. But the views are beautiful.
Some travelling notes
Port Burwell Provincial Park Ontario is quiet and on the enormous beach of Lake Erie. For a more touristy beach day, go to Port Stanley which is near by
Check out the site of the Niagara Wine Escape (Riverside Park Motel and Campgound) if you want to explore Niagara Falls area.
https://www.escapeforum.org/forums/f...3-a-24353.html
Driving through Toronto is a nightmare. Prepare for it and be relaxed and you will be OK. You might consider crossing at Niagara and exploring Sodus, Oswego and the finger lakes areas.
If you want to explore Toronto, suggest camping at Darlington Provincial Park, and driving a few miles to the Go Train and heading downtown from there. Toronto downtown is a great city to explore. St Lawrence market, Center Island, Queen St West, Ontario Gallery of Art, Royal Ontario museum, CN Tower, Blue Jays baseball
The 401 is the main (I-style) highway through southern Ontario. Once you get past Toronto, highway 2 offers more interesting driving through apple orchards, beside Lake Ontario and the St Lawrence River, all the way to Quebec. If you like, Highway 2 becomes highway 338 in Quebec, offering the same scenic drives. Take highway A30 to get around Montreal from the south, or A40 through Montreal.
Take A40 to Quebec City on the north side of the St Lawrence River or A20 on the south side. A40 is more scrub brushy and hilly, and A20 is pastoral and flat flat flat. Or if you like take A15 to the Sherbrooke area – Lake Magog, Compton, Orford are gorgeous, hilly, green areas with lots of camping. If you do that, you can cross into Maine at Coburn Gore for a very scenic drive through Maine to Calais, and then to St Stephen.
[Both Montreal and Quebec City are interesting cities to explore. Like any big city, the historic downtown cores are more interesting than the suburbs. Quebec City is more historic and interesting IMHO, but both are worthwhile.]
If it was me, I would definitely drive the much more scenic north shore from Quebec City to the ferry at St Simeon, then cross the river to Riviere-de-loupe. Drive into a meteor crater at St Paul. The A20 continues on the south shore from Quebec City and it is more scenic flat flat flat farmland. Both routes are attractive.
Please PM me if you would like more information. I haven't brought my new-to-me trailer east before, but it is on the list for Aug-Sep this year after it gets a bit quieter.