Outside Toronto
I'd recommend taking a 2 hour trip up to Collingwood's scenic caves to get a sense of Ontario's natural beauty. Watch a virtual tour below.
http://www.sceniccaves.com/green/caves-trails.htmJust outside Toronto is the renowned McMichael Art Collection situated in the beautiful Klienburg Conservation Area.
Largest collection of Canada's Group of Seven painters as well as First Nations artists and other Canadian artists.
http://www.mcmichael.com/about/If you go to the Niagara I'd recommend also visiting the Butterfly Conservatory which is 10 minutes N of Niagara Falls. 2000 butterflies in a rain forest setting.
http://www.niagaraparks.com/garden-trail/butterfly-conservatory.htmlIn Toronto, aside from the regular attractions like the CN tower, museum, science center, art gallery, I'd also suggest visiting Black Creek Pioneer Village (very authentic) which is accessible by public transit and takes about 30 minutes from the downtown. A Toronto Transit day pass is 10.00, weekly pass 36.00.
http://www.blackcreek.ca/experience-the-village/And don't stay downtown to eat though places like Fred's Not Here and the Red Tomato on King are fun. Go to Little Italy (Cafe Diplomatico on College has the best pizza and a great patio. Always packed. Go to greektown which also has great patios. King Noodle at Spadina and Dundas in Chinatown (minutes from downtown) has great noodle dishes and fantastic barbecue duck and pork. Getting on the Queen streetcar and going west out to what called the Beaches is fun and it has some nice outdoor patios.
If you like strolling. I'd suggest strolling one evening through Rosedale, one of Canada's oldest and wealthiest neighborhoods. Wonderful tree lined winding streets and Victorian mansions. It's only a 5 minute subway ride from downtown. Get off at the Rosedale subway station and wander East. Nearby on Yonge is the small funky Rosedale Diner. Another nice place to stroll is the Distillery District.
Toronto's neighborhoods are far more interesting than the waterfront which is now a cavern of condos. The only thing that saves it are the Toronto Islands which you can reach by ferry. An interesting fact I learnt recently is that Toronto has the most Victorian architecture than any other NA city. A beautiful example of it is the Ontario legislature building at Queens Park, imo its worth taking a tour if you like that sort of thing.
The other thing I'd suggest since you have so much time is check out hospital row on University Ave just south of Queens Park to get a bird's eye the primitive horrible facilities Canadians endure under socialized medicine. Sick Kids hospital's huge soaring light filled atrium is just pitiful. :sarcasm:
Lastly I'd suggest you eyeball a phenomenal thread called Toronto Then and Now. A photographer who is a history buff gets old photos from Toronto's archives and then takes exactly the same shots today. Its a terrific thread.
http://urbantoronto.ca/forum/showthread.php/6947-Miscellany-Toronto-Then-amp-Now