We have picked up and dropped of rentals cars in Chiusi several times and it is so easy! The car rental location is across the street and down a half block from the train station. I am working on the same scenario right now. We are going going to be in Assisi and then heading to Rome for a night before heading home. Normally, we always drop our car in Chiusi and train into Rome. This time Letizia is suggesting dropping our car in Foligno because its close to Assisi and has quick direct trains into Rome. The only disadvantage in the car rental is not directly at the train station. We would have to take a short cab to station. It makes me a bit nervous to do that but she assures me it's not a problem.