If you want to be near Denver but up a little in elevation, how about
Chief Hosa CG? Never stayed there, but it is fairly close to Denver and at 7700' a little cooler. Don't know about limits on how long you can stay there. Most of the nearby SP's have such limits.
As noted, you don't need to be near Denver to have some amenities. Many of the Front Range cities have everything you are asking about. How about Salida (or Buena Vista), which have restaurants and a Walmart but is only a couple of hours from Pueblo. Or Durango, which has many different stores. Or head out west and camp near Montrose or Grand Junction. You may have a problem getting into the more popular CG's as we are well into the camping season and many are filled for the summer. Many sites are filled with seasonals that return year after year.
