The GMC Jimmy Casa Grande was a collaboration between GM and Chinook Mobilodge, a manufacturer of self-contained motorhomes and campers, being best known for their Toyota-based camper conversions.
The base Chalet/Casa Grande packed everything one needed to tame the great outdoors, including the kitchen sink. There were sleeping accommodations for two, seating for four, a dinette table, a stainless steel sink, a potable water carrying capacity of five gallons, a two-burner lpg stove with a stainless-steel top and an icebox. Upgrading to "Option Package Two" gained buyers a refrigerator that operated on lpg or on electrical power via an auxiliary battery and an AC/DC converter. Option Package Three increased sleeping capacity to four with the addition of a pair of overhead bunks of questionable space and comfort.
https://www.hemmings.com/magazine/hmn/2009/04/Blazer-Chalet-and-Jimmy-Casa-Grande/1795791.html