I’m halfway through a shed based cabin build. 350 sqft plus two lofts and 16’ x 12’ deck. Build details are in the outdoor forum. It’s going to cost me right at $80k when complete and I’m doing it very high end. Eg copper surround and commercial spa shower, etc
Like most people said outside city limits there are no building codes here. However, if you want to connect to the grid for electricity, you will have to get an electrical inspection. I’m a couple miles from the road so it’s cheaper for me to do solar than run electrical and give an easement to power company.
State wide in TN there is a permit required for wells and septic but several builders seemed to just ignore it. I’m doing rainwater collection and using an incinerator toilet so I don’t need either anyway.