Ride the Rockies is a different event from the Bicycle Tour of Colorado. RTR is usually the week before BTC, and entry is done by lottery. BTC is open to anyone. RTR is typically a point-to-point ride. BTC is a loop, starting and stopping in the same city. They both tend to end up in the same area of the state, perhaps so that support systems can stay in the region (food vendors, bike shipping company, luggage transfer folks, Portapotty company, etc.) I did RTR last year and I'm planning on doing it this year. If I didn't get in, I was fully prepared to try out the BTC. From what I can tell, they're very similar, except that BTC sounds like they have better food options at the rest stops.