When I think remote wooded area my mind goes to western NY around Allegheny. I know (and helped) someone who self-built a house in that area but am not sure about what approvals they needed/sought for it.
Places with water (and therefore trees) tend to be already spoken for in most of the US. Alaska, maybe? But that's not temperate at all, and is not great for the solar aspect.
A quick google image search shows a very hot Arizona.
As someone who enjoys following a lot of youtube self-builders around the world I get the impression that most channels I follow have to thread their way through some pretty convoluted and not-self-build nor budget-friendly rules :(
Do you know of any other places in the US that have similar easy-to-self-build but are more wooded and temperate?