A few things I should have added from our phone chat, Denis.
If you have the time to be your own general contractor so to speak, run the subs for electric, grading, slab, water if required, etc. the price is impacted in a positive manner but your time and effort also has a cost.
I saved a lot of money on the barn rebuilds by knowing where to source used components, especially windows and lights. I also did a lot of trades, especially for the guys who liked to hunt and fish: Three days in the Duck Blind buys a lot of finish carpentry...a season in a deer stand got the electric put in
I have no other discernible skills to trade but you do.
Speaking of skills, you will save a bunch because you have enough skill to do a lot of the grunt work plus the wrap up stuff - paint, insulation, slab seal, etc. Even I could manage that.
Sounds like a great project in a part of the world I really like.