By Plane Or Train
The most common starting points for a tour of the Rhine Valley are Cologne, just north of Bonn, and Frankfurt, just east of Rüdesheim. Frankfurt is actually on the Main, not the Rhine itself, so the Rhine towns of Mainz and Wiesbaden also make popular starting points.
By Cruise
A large number of luxury cruise operators sail up and down the Rhine from Amsterdam to eg. Basel, Zurich or Strasbourg. The leisurely journey with plenty of stopovers typically takes anywhere from one to two weeks, with accommodation on the boat itself. Large operators include Avalon (http://www.avalonwaterway...) and Viking (http://www.vikingrivers.com/), with low-season prices for a 7-night cruise starting from around US$2,000.