The only thing I'd suggest is buy a very reasonable used pop up tent camper that is in good shape. I can't seeing you dropping too much money for only 3 outings a year. My first thought was that you should just rent a cabin when you want to go camping if there are campgrounds/parks near you that offer rental cabins.
Or...just invest in a good tent and other gear (stove, lantern, sleeping bags, cots, etc. and get a little utility trailer that can serve as a camping trailer i.e camping gear stays loaded in the trailer so when you want to go, all you have to do is pack food and clothes.
