this was my very first century
And I come from an elevation of about 1200 ft. I traveled to CO about a week ahead of time to get used to the elevation and had absolutely no problem at all with the ride. There is some climbing but nothing bad. The support is amazing; the rest stops are great - including ice cream! - the scenery is to die for, and there is a big party (**free beer**) at the end.
It was a great experience - you get lots of "stuff" including a jersey and I highly recommend it.
Oh jeez - can you tell I posted this while I was at my office? I forgot to add the link! Here you go:
http://www.vailvelo.com/riverride.cfm
Thanks for the PM, three - I never woulda known! Sorry about that!