Spend one night along the Rhine (Hattenheim, Assmannhausen, Oestrich-Winkel, Oberwesel, St. Goar, or Braubach) and one alone the Mosel (Beilstein, Bernkastel, or Horbruch). If you include Trier and Luxembourg in your sightseeing, allow two nights along the Mosel. As you travel along both the Rhine and the Mosel, know that there are a limited number of opportunities to cross back and forth between their banks. Study your map to plot your route to take advantage of the few bridges or passenger/car ferry points. The ferry crossings are frequent and inexpensive.
This Itinerary begins in Frankfurt, conveniently reached by direct flights from cities throughout the world. If you arrive at the Frankfurt airport, you can easily begin your journey immediately by picking up a rental car at the airport and starting on your way. If you choose to visit the pleasant, modern heart of the city, be aware that a couple of the historic gems have been restored.
For a detailed description of this car rental driving itinerary Auto Europe highly recommends Karen Brown’s Guide to Germany, Charming Inns & Itineraries.