Well like RR said you could take the Schuylkill Trail from the Art Museum out towards Manayunk which is a trendy little town with some nice sidewalk cafes and a brewery and a (!!) ice cream shoppe on mainstreet. We like to ride out there for lunch some times. If you want further distances, wend your way through Manayunk to where the trail continues westward (this can be a bit confusing as you have to make a few turns and there are some hills and much traffic on a weekend) and take the trail all the way out past Norristown and Conshahocken to the Valley Forge connector trail and check out the historic sites. Not sure if that's too much distance though, It would be probably at least 30 miles each way (can you tell I never ride with a computer?). Alternately, from Manayunk if you have knobby tires you could go up the hill to your right and past the bus station, cross the street and get onto the packed gravel trails of Wissahickon and ride on those too.

K.