Whatever your comfort level, there's no need to spend more than you have to in Europe. In most cities, subways and buses are clean, safe and reliable. Rail travel in Europe is fast, efficient and economical. Take the train whenever and wherever possible. Many rail pass plans are available.
More information is available at the company's web site , which also accepts bookings.
Many local travel agents can sell you various rail passes. Driving in Europe used to be fun, and it's still easy to drive away from the cities. But in cities, the congestion and parking are royal pains and not worth the effort. If you must drive in Europe, make your rental arrangements in the United States before you go. The rates are much better.