Here in Upstate NY the streams are loaded with crawfish. Turn over a rock that's in the stream and more often than not you'll find a crawfish. They are not very big and I catch them by hand. They make great bait for a lot of different fish including large and small mouth bass, trout, perch, and catfish.
Good luck with your new endeavor.
RE: Crawfish in Colorado? I just bought 6 traps!