The old way to deal with the roof was to bundle it with faggots. Rushes, bracken, heather, tied up brash, whatever was on the site or around the area. It lasts about three years before it needs stripped and redone. It insulates both from heat and from the cold.
The other way is to make double hurdles and stuff the space with bracken and the like.
If you have a fire going underneath then the smoke permeates in and kills of insects and really discourages rodent activity too.
Water ? sand and charcoal filter it. Just have it run through a butt full of layers of grit and charcoal and draw from the bottom. It needs cleaned out and refreshed every couple of years if there's 'organic' debris getting in too. If you cover it and have a rone into it from the roof rainwater, it'll help cut down on the debris and insect infestation. Keeps the newts out too
Boil the water; our guts aren't constantly being assaulted by the 'wild bacteria' these days, so it makes sense. Make tea or coffee, and when you cook with the water make sure you do bring it up to the boil.
For washing /brushing teeth/shaving, etc. just keep a big kettle on the fire or side on to it. It'll boil up quickly, and it means there's always 'clean' water. It just becomes habitual to think raw or clean.
The cabin sounds excellent
I hope it's a pleasure for years to come.
M
