We stayed in the Crested Butte Campground last June. We have "camped" in that area for many years, but this is the first time we were able to stay in Crested Butte. Always before we had stayed in Gunnison and only drove up to Crested Butte. This is a new campground and we enjoyed it greatly.
There is no sewer--no dump station. You are right beside the river and have a magnificent view on the western horizon.
For our part, our stay was not long enough to have problems with the holding tanks. We towed back to Gunnison on the way out (downhill all the way) and dumped in an RV park there (yes, there was a charge.)
Have a great time in Crested Butte and the Gunnison area. Try to make a trip up the Taylor River and Spring Creek roads from Almont. If you have time keep going over Cottonwood Pass to Buena Vista over in the Arkansas Valley. Gravel road up to the pass, paved all the way down into Buena Vista.