Going to Canada is going to another country, and border crossings are pretty serious places these days. However, Canadians love Americans to come to Canada so assuming you have good identification and are just vacationing you'll be welcomed in Maritime Canada. Good identification is either a passport or a certified birth certificate with photo identification. You can find more information on going to Canada at this US consular website.
If you're in my neck of the woods, Roanoke, Va, a driving trip to Canada takes a couple of days. It is a little over 1,047 miles to Woodstock, New Brunswick which is just over the Canadian border. It is a long ride but it really is worth it. I recommend going straight up Interstate 95 (The Maine Turnpike) once you get into Maine. You can cross the border into Canada at Houlton, Me. Once you get into New Brunswick, you can slow down a little.
The first place I would recommend visiting is King's Landing, a historical settlement similar to Williamsburg.
You will find over 70 historic buildings, complete with artifacts, furniture, tools and equipment. The history is real, the stories you hear are true. Staff are thoroughly trained and immersed in the 19th century to provide you, the visitor, with an authentic visit to New Brunswick in the 1800s
The table below the map on this web page can give you some ideas of distances from King's Landing to other locations in the Canadian Maritimes.
If the weather is nice, spending a few hours walking around King's Landing is a great way to unwind after all the driving. You'll switch over to Atlantic time once you get into New Brunswick. So nine am Eastern Daylight Time becomes ten am Atlantic Daylight Time. King's Landing's hours are from ten to five daily so you can spend a couple hours enjoying the site, then enjoy lunch at the "The King's Head Inn" and spend another couple of hours walking off lunch and head off to Fredericton. Fredericton is the capital of New Brunswick and only twenty minutes south of King's Landing.
There is enough to do in Fredericton for a quiet evening. This website will give you some thoughts on how to enjoy Fredericton. You can unwind and get ready for the next leg of journey which will take you to Charlottetown, PEI. The trip according to my Google map should take something over four hours.
Once you get to Charlottetown, get ready to really start relaxing. Prince Edward Island is a magical place. You can stay in Charlottetown because nothing is very far away. Plan on spending at least a couple of days. Take a day and go to the beaches on the north shore, enjoy a Lobster church supper, and take in Anne of Green Gables musical at the Confederation Center. After you are finished enjoying Prince Edward Island, the next stop on your journey should be Halifax, Nova Scotia. The trip should take around four hours.
I recommend staying in downtown Halifax and use it as your base of operations. Halifax is a wonderful town to walk around, see the historic sites, and enjoy the great dining, wonderful people and beautiful ocean side setting. Make sure you visit the Halifax Public Gardens and the Halifax Citadel which is my favorite fort. Depending on how much energy you have left after visiting Halifax, you can take another few days and visit the "Cape Breton Highlands National Park" perhaps catching the "Fortress of Louisbourg" along the way. Be warned that it adds a lot of driving and has been know to be fogged in for a few days, but the mountains coming right down to the sea can be spectacular.
You can take a couple of short cuts on the way out of Nova Scotia. They all involve car ferries which take you either to Saint John, New Brunswick, Bar Harbor, Maine, or Portland, Maine. I recommend driving down the Annapolis Valley and catching the ferry from Digby to Saint John. The ferry is short and it is impossible to not enjoy a drive down the Annapolis Valley. If you want to enjoy a little of Acadian Nova Scotia take the drive down to Yarmouth and catch one of the ferries to Maine. Apparently there is a new one, The Cat, that saves a day of driving according to their website. It takes you into Bar Harbor and you have to make the drive to Yarmouth to catch it, but even with that factored in I suspect it saves substantial driving. I will likely give it a try my next trip up.
You can view some great shots of the Valley at this Annapolis Valley website. Make certain you at least catch the ones of Port Lorne and Hampton which were the two fishing villages on either side of our first home in Saint Croix Cove. If you have time stop by Bridgetown and have some fried clams for me at what I have been told is a very good clam spot, The End of the Line Pub. Their menu looks like a good way to say goodbye to Nova Scotia. Trust me it won't be very hard to find. Nothing in the Annapolis Valley is hard to find.
Good luck on your trip, you won't regret the driving. You'll see some spots with enough beauty to take your breath away. It is a little like going back to an earlier time so relaxing isn't very hard. Don't be surprised if you find some self service fruit and vegetable stands along the way and lots of friendly people, great seafood, and wonderful sites.
This link leads to pictures of our adventures in Nova Scotia during the seventies.