-- Last Updated: May-28-12 1:03 AM EST --
didn't see large lakes near Toronto. Going farther, some large lakes appeared surrounded by development.
What looked more promising were some long, narrow lakes to the east of the town of Bobcaygeon. The lakes had less development on shore, and there were interesting clusters of islands in places. That the lakes had differing orientation might help depending on the direction of the wind the day you are there.
Bobcaygeon is sort of NNE from Toronto. I forgot to take a crow flies distance estimate, but maybe those lakes are within a couple of hours drive.
I also forgot to check your profile for your starting destination, but if you're sort of midwest, try driving up I-75 through Michigan and entering Canada at Sault St. Marie. Then you can drive west along the north shore of Lake Superior, or east to Spanish River and Killarney. We spent some nice days paddling lakes just west of Killarney and didn't have to mess with permits or campsite assignment.
Oh, Philadelphia. I was at Penn in the 60s. I guess you might go across at Niagra and cut back to Toronto. Got your passports for the border?