The "E" trail in Eastern Ontario is one of the main backcountry routes through some spectacular scenery. Judging by all the signs that have appeared along the trail this spring, you now need a trail pass to access this route without risking a fine. Whatever; I got the pass ("Gold Pass", $149--see thetrail.ca or pick one up at Carson's in Perth) so now I ride guilt-free. :-)
Here's a pic of the typical terrain. Knobbies highly recommended but not entirely necessary unless you're on a heavy bike or are comfortable sliding around on gravel dual-track. Bathing suit a nice accessory--there are many clear lakes to jump into on hot days.