The Lebanon Valley Trail is a 15 mile trail starting in Lebanon, PA and ending at the Conewago Trail. The trail offers a mix of landscapes and has a bit more ups and downs than most rail-trails. With the direct connection to the Conewago Trail you can get an additional 5 miles in. It has a short spur that takes you to Mount Gretna, a small arts themed community that bills itself as the Chautuqua of Pennsylvania.
When I rode this trail I found Mt. Gretna a nice place to stop for lunch. My wife doesn't ride much and I don't care for amusment rides so I rode this trail while my wife visited Hershey Park with a friend. We were all happy with our experiences at the end of the day.
You can learn more about the Lebanon Vally trail here: lvrailtrail.com and Mt. Gretna here: mtgretna.com