Maybe a Scout group near you perhaps? We have quite a few home schooled boys in our Troop.

I'd have to think you don't have to go far in NW WI to find some woods. Surely your family has friends with some wooded property once you've camped in your own yard.

With zero or little income it will be tougher but there are cheap options for most things - window shrink film for winterizing a patio door as a tarp (and the groundcloth), alcohol stove from a cat food can, etc. The paper I wrote was intended for new Scouts so it should give you some ideas.