We are backpacking/riding Eurail to Rotenberg, Munich, Salzburg, Vienna and Prague from July 1-15. We will need only basic hotels along the way. Do we need to book hotels prior to leaving the U.S.
Not unless you want a room. Anytime you are traveling in the summer in Europe, remember that you are traveling with about 20 million Europeans and auslanders at the same time...
Jennifer, you're traveling peak time. You may get lucky with hostals, but even then many require a reservation.
When I was in Germany, I used www.hrs.de and got great rates for basic hotels, almost all included breakfast.
Jennifer, normally if one has a car I would say fine go for it, my family travels that way, BUT , we lease a car. This enables one to look for places outside of towns, or stop at highway motels where there is always a room.
Since you are on foot and train you will likely find it alot harder to locate a decent hotel by walking around. Not impossible though. Just remember to look for a room as soon as you arrive in a city, no later then lunch time . You may also have to pay more then you want as you will just end of taking what you can find ,, and the good budget hotels are booked weeks and months in advance.. I know I started booking in Jan for this July, and that the rates I got have now gone up for my same dates.
Still time to check out lodgings on tripadvisor.com and similar travel websites. True, if you are flexible and can stay a bit out of town your choices may be fewer but there you may find unbooked rooms. Consider using excellent public transportation (bus, S-Bahn)to take you there. No bets on Rothenburg, though.