While I'm not in the habit of going backpacking, I have two versions of camerapack for longish walks in the mountains:

Heavy: Linhof Color, 4 holders, 5 lenses, spotmeter, changing bag, wooden tripod with heavy ball head.

Light: Perkeo I, an extra roll of film.

I have no idea what a stone weighs, but my gene pool is all viking

Ole