Lately I've been working with buyers on rural properties in Ravalli County.  Rural homes have a different set of issues than urban homes do, and a wise buyer will go the extra mile to check such items out.  Here's a partial list of the things I think deserve attention before the purchase:

Septic System:  get it pumped and inspected so you know what you're getting into.  Also pull the septic permit at the county to insure that the permit size, based on the number of bedrooms, matches the home you're buying or will build.

Well:  it's great to be off the grid when it comes to water, but remember that the well log or water rights certificate may not really represent the well's actual production.  Get it tested, both for quantity and quality (you might as well know if you'll need a water softener right away). 

Propane Tanks:  be you sure you know if the tank is owned or rented by the seller, and if it is being transferred to you, how you will handle the value of the fuel left (or not) in the tank on sale.  If it is rented, you'll need to contract with the vendor to keep the tank on-site.  Oh, propane tanks can be buried (avoiding the giant metal thing in the yard), so just because you don't see one, don't assume it's natural gas. 

Home Inspections:  always do a home inspection, even on new construction.  We Bitterrooters are hardy and independent breed, and like to do many home repairs and construction ourselves, sometimes with varying success.  I am just as guilty of this as the next guy.  With no real permitting process in place, it is important to have a professional's perspective on the home.