We built ours in the Adirondack Park, check any local/state reg's closely before building or buying any land.
We have 8 acres that adjoins state land and opted for a hard build rather than a camper as moisture is a real issue in sub freezing weather inside a propane heated camper.
I have basic building skills and as a family we did all the work ourselves with three pre-teen's and only hired local help with the roofing for a day. It took us less than 40 days of actual work to have it completed and we can upgrade as the future allows (additional storage/toilet). We utilize an outhouse and have no running water currently. We have a high water table on the land and hope to put a battery pump inside a dug well for a toilet/septic and shower installed in a small addition at some point.
But for now we obtain fresh potable water from a local spring using covered 5 gallon pails with the UTV as transportation on a semi-daily basis.
We have propane lights, propane fridge and run off a 100 lb. bulk tank year around, we heat with a wood stove and are currently not insulated. The building is 12 x 24 with a 4' wall upstairs and a steep roof for added head room and snow shedding ability. We have a small Honda generator for things like battery charging and very rarely a window fan at night in the summer.
I designed the camp myself, ordered the lumber and carried windows and supplies in as we built. It really became a "labor of love" and after hard work and lots of "camp candy" (Tylenol) we got it done and enjoy it greatly.
Good luck and it's great you are planning now and buy/build once...
Cost: land $ 25,000.00
Camp $ 16,000.00