We love this charming riverfront town.Credit: Brown W. Cannon IIIAt the precipice of the 4.5-mile Maryland Heights Overlook Trail, the small town of Harpers Ferry appears as if from a 19th-century dream. One minute you’re trudging through dense deciduous forest, the next, the trees abruptly part to reveal a rocky cliff overlooking the tranquil mountain town.From here, you can make out the colorful rooftops of Harpers Ferry’s Lower Town, where Vi…