BIZZ JOHNSON TRAIL: Susanville, CA - This gravel/ballast trail is the longest rail trail in California at 25 miles in length. The gravel surface is best suited for fat tires and soft saddles, and visitors are advised to bring ample water and resources for the journey. There are no services between the two endpoints; what you carry is what you'll have to use. Also, the trail is at the mercy of the seasons and may be under snow during the winter.
Wisconsin: Elroy Sparta Trail - With three rock tunnels and five small towns along it's 32.5 mile route, the trail is a favorite Wisconsin bicycling destination. Traveling between Sparta and Elroy, the trail stretches through the communities of Norwalk, Wilton and Kendall.
Trail Link - If you are going to bookmark one site, this is the one. This is the most comprehensive list of rail trails in the USA. - Rails-to-Trails Conservancy is a nonprofit organization based in Washington, D.C., whose mission it is to create a nationwide network of trails from former rail lines and connecting corridors to build healthier places for healthier people.
5 Great Pennsylvania Rail Trails Bike Trips for the Entire Family