As GreatWhite has already stressed, the Cabot Trail is a "must see" when in Cape Breton. Many maritime bike meets have had the trail on their itineraries. Only thing - if it's foggy, you don't get the full effect, because the road hugs the seashore, and often the water is not visible at all. Best to do the trail when it's clear.
Also in C.B., the Baddeck region is a good spot for a minor layover. Alexander Grame Bell summered here, and conducted many of his experiments in flight on the waters of Bras d'or Lake. There is a very interesting museum at Baddeck dedicated to him.
The fortress of Louisburg is also a hot spot for tourists when visiting C.B. Totally reconstructed in the '60's (a make-work project at the time), it is a huge site, with actors dressed in period costumes, and many displays of 17th century fort living, even a restuaurant with period menus and pewter cutlery. The fort changed hands several times between the French and English, as they were both trying to establish ownership of the "new Land" Even sunken warships in the harbour, which I once checked out during a diving excursion.
As usual during vacations, lots to see and do, but not enough time to do everything!
Stay safe in Newf, go easy on the "screeching in" parties