My wife and I will be traveling in Germany for 3 weeks next August and want to take a 3-4 day cruise on the Rhine. Should we secure reservations prior to leaving the US and if so, what company is the best? Where would be the best embarkation city and debarkation city? Thanks, Dorsey
You should probably check out cruisecritic.com. Their boards discuss a wide variety of cruise options, including river cruises.
I've been on cruises as have, I think, many on this site but cruise specific information is better at cruise critic.
Here is a list of river cruises at the site:
http://www.cruisecritic.com/cruiseto/cruisetoresults.cfm?action=all&sort=shipname
None of them seem to be only 3-4 days.
If you see one you like, go to reviews to see what people who have been on the cruise thought.