Greetings and welcome to the board! I escaped from Cali back in September. Idaho has been great to me so far.
The gunshops I can definitely vouch for are Sawtooth Tactical, Ambush Tactical, and Hawktech. I recently got a membership to the Nampa Rod & Gun Club, it's a nice place to shoot. Of course a lot of people here just go out to the desert area south of town and shoot.
Again, welcome to Idaho.