Mr. Dvorak may have been the first commercially permitted river rafter in the state of Colorado, but I am confident he is not the inventor of river rafting, since Georgie White http://en.wikipedia.org/wiki/
It is equally ludicrous to attribute Mr. Dvorak with the being the one to first conceive of the idea of having guides lead raft trips. Bill Dvorak has been rafting for a very long time but 1969 still makes him a 'pup' among some river rafting outfitters. http://orionexp.com
"The person generally credited with inventing river rafting is Bill Dvorak"
- River Rafting An Overview (view on Google Sidewiki)