As a geographic note, Nova Scotia, New Brunswick, and Prince Edward Island are collectively known as the Maritime Provinces, or just "the Maritimes". Add Newfoundland and Labrador to the mix and they become the Atlantic Provinces. The distinction is due to history, as Newfoundland didn't join Canada until after WWII.(...) I'm more than happy to explore NS, NB and nip over into Maine to get a fix of the Good ol US of A (avoiding Quebec - your not French so stop trying). She does like the idea of Niagara so I could maybe sell her on heading for Buffalo and back as long as there's a suitable waterpark along the way (promises have been made to the actually important female in my life).
In New Brunswick the St John Valley is the longest settled part and where the population is concentrated. The main settlement wave came as refugees from the American Revolution were evacuated there before the British pulled out of the rebellious colonies to the south. These people are referred to as "Loyalists", so any tourist sights advertised as being in connection with "Loyalists" is likely to have some sort of historical aspect to it. As a side note, more of the Loyalists pushed on up the St John Valley on foot and by ox cart, up the St Lawrence, and then into Ontario. Thus there are many references to Loyalists in Ontario as well.
The Bay of Fundy has the highest tides in the world. You may want to keep a tide table in mind if you intend to visit anything along the shore line. The Flower Pot Rocks, also known as Hopewell Rocks are one of the classic tourist sights. They are pillars of rock rising out of the sea along the shore. If you plan to visit them, keep the tides in mind and plan accordingly. See the link below for information.
The Hopewell Rocks is a place to pause…a place to appreciate a remarkable story interwoven through time, tide, and the intricacies of nature. These are the highest tides in the world. And they happen twice a...
There are tidal bores in the rivers emptying into the Bay of Fundy. The one on the St John River known as the "Reversing Falls" is the most famous, but there are others as well. On some rivers there are rafting tours which let you ride the tidal bore (recall that the Bay of Fundy has the highest tides in the world). Again, remember to consult tide tables if you want to see them. The size of the tidal bores will depend upon the phase of the moon, as that affects the height of the tide. Some people surf the tidal bores, but it's not likely something you can plan to fit into a vacation.
The area is also known for covered bridges, and includes the word's longest. The smaller ones are more typical however. The design of the bridges was originally intended to reduce maintenance requirements by keeping rain and snow off. They are now considered to be quaint tourist attractions. Here is a typical example.
In Nova Scotia, Cape Breton Island is considered to be exceptionally scenic. The Cabot Trail highway loops around the north end of this large island, through mountains and along cliffs above the sea. There is a specific direction which is recommended to go, but I can't recall which it is. I think it's counter-clockwise, but you may wish to confirm that. It's been a while since I was there, but I can recall some spectacular views.
The area was settled by Scottish from the highlands, but then later largely bypassed by progress until recently. The result is that there is still a heavy older Scottish cultural influence.
Also on Cape Breton Island is the Fortress of Louisbourg. This is a reconstruction of a French fortress town which was built as a base for the French fishing industry. At its peak it was the third busiest port in North America. Halifax was built by the British to counter it. It was well located from a commercial point of view, but poorly located from a military perspective and so indefensible from the landward direction in any practical sense despite the walls. Britain captured the town during the mid 18th century, ejected the population, and destroyed it. It was partially reconstructed on the same spot in the 1960s as a tourist attraction (and as a make-work project, as the area was economically depressed with the decline of coal mining).
Another sight is a museum at Alexander Graham Bell's summer home, Beinn Bhreagh. There is a large lake in the middle of the island (Bras d'or Lake) which makes the island rather like a doughnut, and Bell's home is at the northern end of it. The house itself is still privately owned by his descendants and not open to the public, but there is a museum dedicated to him nearby. After he made loads of money in the communications business, Bell continued to experiment in many areas at his home here. His work included experiments with aircraft and hydrofoils. One of his planes made the first flight in the British Empire. There's lots of Bell related artefacts in the museum.
Hydrofoil in museum.
The only town of any size (and it's not very big) on Cape Breton Island is Sydney. It's an old coal mining and steel town which went into decline in the latter part of the 20th century as the steel and coal industries closed down. There's nothing to see there so far as I am aware.
PEI (Prince Edward Island) has some nice sandy beaches, but a day on the beach will depend on the weather. There is a tourist attraction known as Anne of Green Gables House. For some unfathomable reason the Japanese tourists are (or at least were, last I heard) bonkers over it. Be aware that Anne of Green Gables was a work of fiction by author Lucy Maud Montgomery and the house is based on the novel about her. Various plays, films, and television shows were based on the novel of a young orphan girl growing up in rural PEI in the late 19th century. The house is intended as a representation of Anne's (fictional) life. Whether or not this appeals to your daughter will depend on whether she's a fan of that sort of thing, but it's one of the classic children's stories and well known around the world.
If you're in the Maritimes you should of course plan on eating sea food at least occasionally. The area is a big producer of lobster, so if that appeals to you it should be readily available.