That camper with the sewer cutout is, an "El Dorado". It was made in La Mesa, CA. and by a company called, "Honor Built", ( guess long since defunct.)
It's marked as being a 1974, but has held up quite well out here on desert trails. It IS VERY heavy, so a 3500 is needed. With three big solar panels, and a 3800 watt genset, as well as flat screen and DVD player, Microwave, and even a nice shower, you can be quite comfy out for several days. Strange thing is....it has no heater, or a/c.