The abandoned Kingston & Pembroke ("K&P") railway line is a great jumping-off point for some interesting trail rides west of Ottawa, including the E Trail and its numbered tributaries. Following the K&P from Sharbot Lake to Calabogie, or all the way to Renfrew is a beautiful ride--especially in late summer. There are many lakes and endless forest, so even though the line is straight and you have to pay attention to your front wheel, it's a great introduction to backcountry riding in the area.
These photos are from along the trail and a sidetrail, and in the ghost town of Folger, a whistle stop on the K&P just north of Lavant Station.
The K&P is pretty good gravel overall, if narrow and potholed in places. A road-oriented dualsport tire is fine as long as you don't go too fast, and you avoid riding early season (lots of ice remains in the shade) or when its wet (some mud and minor gravelly stream crossings that look worse than they are). If you have knobbies, I highly recommend the side trail cutoff just north of the old railway bridge about 3km south of Clyde Forks. Watch the trestle crossing because the planks are parallel to travel and spaced to catch motorcycle tires. The cutoff ascends a sandy hill (seen in the pic looking back to the K&P), then the trail becomes a loose dual track with lots of ups and downs. It's some wicked riding for a dualsport and not at all recommended for street-oriented tires. Trail pass and maps are advised--you're really in the sticks out there.
This whole area saw its heydays start around 1880 with the coming of the railway to support the square timber industry and the discovery of iron and other minerals in the area. In fact, near Lavant Station in 1881, a community called "Iron City" was surveyed to support two local iron mines and a copper mine. Lavant Station once hosted a sawmill, hotels, and a post office. It's hard to imagine now that 130 years ago a few hundred people lived in town out here and this was one of the up-and-coming frontier towns. By 1911 it was all ghost town, and in the 1950's a lot of the old structures burned in a massive bush fire. One of my maps shows a possible location for the iron mine. I'm going to see if I can find it.
For a great read about the history of the area, I recommend the fascinating book "Whiskey & Wickedness - No. 3" by Larry Cotton (www.whiskyandwickedness.com).