We live in Colorado Springs but traditionally hit Mueller at least once a season while we had a pop up. Not quite as good for our current RV - there are devil trees to maneuver around! It is a beautiful wooded park with lots of trails. Sites vary in size and type with a few pull throughs. There are 3 very nice fully-equipped cabins also. If you're into geocaching, there are several that can be found in the park. Beautiful place to get away and enjoy nature.
A lovely wooded campground literally on the edge of Rocky Mountain National Park - we even saw moose from the back window of our RV! Options for everyone from cabins, to FHU RV sites (limited and not the ideal locations, but still nice), water/electric sites and tenting areas. Even Conestoga wagons! There is horseback riding on site and we loved watching the horses run in and out each morning/evening and you just have to cross the road for a pretty hike along the Colorado River in RMNP (no dogs on the trails). We camped with our Great Dane - very dog friendly with bag stations around the park. Friendly and helpful staff, a small shop with supplies and souvenirs, a cute little petting zoo with goats, sheep, and pigs.