In reply to Scuffer:
The casino rates tend to be better than straight motel rates; they're hoping to get your gambling business. The best rates are Sunday-Thursday, and they can double for Friday and Saturday. If some big event comes to town, like Nascar racing, the rates go through the ceiling.
One of the closest (usually reasonable) casinos is the Suncoast. Perhaps a step seedier but still fine, although further from Red Rocks is Arizona Charlie's.
You'll get more expert information on mountainproject.com and supertopo.com. Somewhere in their forums is a pretty extensive discussion about places to stay, but I just looked and couldn't find it...