Hey Kimberly,
We will be moving into Waldo County around Unity in April of next year, we're just waiting to finalize the details. As for hitting walls are you referencing codes in the area or just with the building process? For insulation there are a few options available to you, you can wider earth bags and do a gravel/clay mix or look into lava rock to see if it's either available in the area or able to be affordably shipped. You could also make the walls two rows thick which should suffice as enough insulation on their own but is literally double the work. Your last option would be to build the shell and then install wall posts, insulation and then sheet rock, like with a standard house. As for the roof a standard roof design would be best, avoid the earth bag dome due to the moist climate. For insulating that it would be just like with any other roof, just making sure you have the proper r value insulation. There is a really great book if yous aren't familiar with it, it's called Earthbag Building by Kaki Hunter and Donald Kiffmeyer. It's a great resource and one of my main sources of information. They go into great detail about insulation options for colder climates, along with building and insulating roofs, I strongly recommend it I got mine from Amazon for like $20 or $30 only. Best of luck with everything and as things go on keep me posted as my girlfriend and I seem to be more or less on the same page as you!