Unfortunately in Colorado this is the time of year to go ice fishing as the lakes and even parts of some rivers are frozen.
The Blue Hole is a 5.5~6 hour drive (400 miles) from Denver, and is located in Santa Rosa, NM. From my perspective there is ONE thing to do in Santa Rosa, and that is to dive. The restaurants are OK, there is no theater, no bowling alley, and really not much for entertainment period.
Crater, UT is essentially a large hot tub, and expensive to dive, but you don't need a dry-suit, or even a wet suit. The water temps are in the 90's I believe. There is no life in the Crater, and they charge something like $25 for EACH dive which they limit to 30 minutes I believe.
Not sure if driving 800 miles is your idea of an acceptable distance to drive to dive. Those of us living in the Denver area make the trip many times a year, but we don't have a lot of diving options here, and Santa Rosa with Three decent places to dive offers year round diving with good vis (BH), and interesting UW topography.
If you are interested in diving BH, post, and I'm betting we can get a group to go down when you are here.