I spent a year abroad here for school so the viewpoint may be a little skewed. I didn't have a car, but the walled in portion of the city was very accessible on foot.
Viterbo, V-Town as I like to call it, is about 80,000 people set in Rome's province, Lazio. Viterbo is a great alternative to Rome, however it isn't NEARLY as big, because it gives you great access to Rome without all of the horrible tourist traps. Viterbo is only 1 1/2 hours by train. The people of viterbo are extremely proud of there city's history and a bit wary of outsiders, but they are def. friendly to anyone that makes an effort to become italian for a bit of their vacation, whether it is a week or 9 months. It is a mideval town with the tiny winding streets and rich cultural history that seems to hang in every city or town in Europe.
Favourite spots:
Best spots were the Piazza Commune/Piazza Plebiscito and La Spaghetteria (which is in the Guinness Book of World Records for having the most types of spaghetti, around 350). The Corso, which is the street that divides the city in two, makes the perfect place for the eveneing walk. The thermal baths, TERME, are a great spot to relax, even if the weather isn't too great.
What's really great:
I liked the close knit community best of all about Viterbo. The scenery was beautiful, but there wasn't much to do sportwise other than bike. There weren't too many hikes, paddles, runs, or climbs.
Sights:
San Pelligrno is the medieval part of the town. There is AMAZING architecture to see along with the stereotypcial italian townhouses. There are usually festivals happening around every 2 weeks so San Pelligrino is a great place to walk and take in the rythym of the city.
Hangouts:
Van Dykes was an amazing pub with the best tequila in the province. The waiters and waitresses dress up in pirate costumes and sing and dance every time the serve you. The bartender, Alessandro, was very friendly and evern tried to speak english when he could see that I was struggling.
Leons is the college hang out, although I heard they were going out of buissness. If you just want loud music and cheap beer leons is the place for you. However, they arent' very friendly to tourists or americans over there, so choose your pub wisely.