We are doing the same, locking in a trip to Crested Butte.
Internet searching appears to be the best bet in and near Crested Butte.
We have had great feedback from the owner’s, had a couple questions, which they answered & followed up quickly. Drop them an email.From their site --
• We do not have sewer connections or sewer dump on site. Crested Butte RV dump station is 2 miles away.
Have done a non-RV trip to Crested Butte, as active Mtn Biker, it is an incredible town & area. Can’ wait for our RV trip, the campground appear pretty incredible, if you have not seen it; they have a cool video review!
VideoMarkiemark:C