Can't let this one go without a plug for my hometown: Salida, CO. Don't be misled by what you find on hwy 285 or 50 -- that's just the commercial strip of which we're rightly ashamed. Head toward downton on the Arkansas River for the real part. Good bars (I recommend the Victoria), lots of art, and amusing, colorful locals. Just about any place in Chaffee County elicits comments like "Oh my Gawd, why doesn't everyone live here
"? I know next to nothing about RV sites there, backcountry sort that I am, except that there are a lot of 'em -- maybe enough that they're not all full on the 4th. Four miles north of Maysville (honk when you pass the old Yellow House) on CR 240 is Angel of Shavano campground. No hookups, far as I know. If you have an ATV or stout 4-wheel-drive, you can go, sans trailer, to the top of that road annd visit my old mining cabin above Billings Lake at 12,000'.
From Salida, you could go north toward Leadville for mining lore or south for ashrams in Crestone. A half-day hike from any of those places will get you to wilderness areas, and another half-day puts you on top of 14,000' peaks.
July is "monsoon" season in all of the Colorado High Country, so be prepared for rain or snow each afternoon, with accompanying shorts-soiling lightning. Mid-September is the absolute best time to visit. Check Colorado Central magazine (Colorado Central Monthly Magazine Home Page
) for more information.