This might not be of interest, depending on where your interests lie, but if you were to rent a car while in Toronto, you could head about 2 hours north to "cottage country" in Muskoka. If you like nature and wanted to see some beautiful countryside, you could stay in Huntsville at Deerhurst Resort and do some sightseeing, then do the cross country route through Algonquin Park to Ottawa. Way more interesting than the 400 and QEW
Of course, I'm partial to the area - relatives and a cottage on Lake of Bays.