Thank you Jaxon for getting started on this. I've lived in Western Colorado for 40 years and agree that this would be a great location for a Tenere gathering. I know all the paved roads and have been in all the towns (at least for lunch if not overnight) in the area. I am just starting to explore the dirt roads as I rode Ducati sport and sport touring bikes for the last 20 years. I bought my Tenere in August of 2011.
Late June is the best time to ride in Colorado. The weather tends to quite stable, warm but not too hot. Evenings and nights are always cool so camping should not be a problem. The Monsoon usually doesn't arrive until July and even then it usually doesn't rain before 3:00 PM. I am saying usually because unusual weather can happen at any time and on must be prepared for anything. But the percentages are favorable for late June. My favorite time to ride is September but I have the luxury of hanging out near home when the weather is poor and heading out only with a favorable forecast.
I like Gunnison but I don't think it's the best choice for a gathering. Gunnison is a historic ranching town (with a medium size college) that has a lot of what is needed for a successful gathering but it does not have the feel of being in the mountains as it is set in a wide-open valley. It's near the mountains but not in the mountains. I think people from the flat lands would be disappointed.
All of the big ski towns (like my home Snowmass Village) have beautiful settings but may be a bit pricey for some and camping is usually not available. I suggest considering Ouray (locals say You-ray). The setting, in a box canyon at the base of Red Mountain Pass (Million Dollar Highway), can't be beat. Most importantly Ouray is the epicenter for dirt riding in Colorado. Many of the rides are better suited to smaller, pure dirt bikes but I am sure there are some rides any of us could enjoy. There is a KOA there and the Best Western would work well for those who demand a roof over their heads. Ther are lots of Ouray based ride reports on advrider.com.
Salida should also be considered. It's near but not in the mountains, is much larger than Ouray (has a Walmart for example), and may have more affordable lodging options. Salida is on the TAT and the CDR so there are lots of dirt roads nearby. There may be more dirt suitable for a large bike near Salida than near Ouray.
I am planning on AK next summer so I won't be attending but I be happy to help in any way I can.
Jeff