Campsites in USA

Does anybody have links for campsites in the USA which are similiar the the ones in say France where you can rent a mobile home and have onsite facilities. We're thinking about going to Colorado next summer (a change from France) but really enjoy the freedom of of the sites and would like to replicate it over there if possible.

start with KOA.com

I think that in the US it's more common to Rent an RV ( "Recreational Vehicle" i.e. Motorhome/Campervan) and drive between campsites parking up to sleep .. loads of people seem to do this

The most common ones you see on the road (out West anyway) belong to www.cruiseamerica.com but I'm sure there's loads of other RV rental outfits there ... I think that this is much more the "normal" way to do a camping holiday in the US compared with renting a mobile home/chalet on a campsite ... It obviously gives you even more flexibility too and it seems to be a really popular holiday.