Jeff & I have been to three NWTRs. Lots of fun! There's nothing like the first day, starting out in a MASS of 450(or more!) tandems/triples/quads, etc. They usually have rides of all lengths - family friendly 20 milers all the way up to 80-100 miles for the fitter folks. I'd definitely recommend it.
We're planning to go again this year, though we may have to bail at the last minute. Not sure yet...
Susan