After seeing much of western Europe, my girlfriend and are considering tackling Germany for the firt time, sometime around the beginning of the year. We must fly into Frankfurt, and we won't have alot of time (about 5 days) or a huge budget to work with. I would prefer to concentrate on areas within about 90 minutes of Frankfurt's airport. We would both love to see some castles, and I would love to experience the German pub scene.
Would you suggest visiting Heidelberg for a few days and then do a few daytrips, or would it be better to be based further west in the river valley area to do stuff? Any itinerary with transportation suggestions would be extremely appreciated!