Re: cabin flooring high humidity

if your going to use wood products, make sure its all pressure treated, i would even use a marine grade plywood for the decking. if you do that and build so you have it just a little off the ground, so air can circulate under it you should fine and it should last you for a good 20 years or so. if your worried it being open and critters or cold, build you some framed walls to the ground and kind of like what a mobile home would have for skirting, as far insulation goes, i would go with nothing less an r-19 value in the floor, r-13 in the walls, and at least an r30 in the ceiling, if your using convential construction materials just your regular fiberglass insulation will do fine. geta foil face batting insulation and just staple it to the floor joist. hope this helps good luck, also if you ever decide to build a community type thing let me know,