Welcome hotrocks.
As far as I know, Idaho doesn't have laws any more strict than Utah.
Go buy the guns at a dealer, and you'll fill out the 4473 registration form, which stays with the dealer.
He will also do a background check on you, over the phone. Usually takes just a few minutes.
If everything comes back good, you pay for them, maybe buy some ammo too, and you're done. Head home with your new toys.
Fingerprinting isn't done, nor is waiting periods, in many states, including Idaho and Utah.
If you're buying them from a private party (classified ads, etc.), then it is cash & carry.
The seller cannot 'knowingly sell' to a person who is not legally able to possess firearms, like felons.
Some other people will want to see a CCW permit, others won't.
eta: If I'm wrong on any of this info, someone feel free to correct me.