Me and my dad are going to be building a cabin this spring/summer. It won't be too far from our actual permanent campsite.

I want it to be small and cozy. I was thinking shack-sized; enough for bed, a counter, a cabinet and maybe a wood stove.

I live in Central WI, so the weather will be either rainy and muggy, or hot and muggy.

(Muggy=humid)

So, any tips? What kind of wood should I use, what kind of roofing, etc.
Any kind of water proof stain I could use?