In Idaho concealed weapons licence is only for carrying concealed.
It is legal to open carry any place not excluded by law.
You can have a loaded firearm in your vehicle even without a concealed weapons license as long as the firearm can be seen clearly from any "reasonable viewpoint from outside of the vehicle to view what is inside the vehicle".
Loaded rifle on gunrack - Okay.
Loaded pistol lying on the dashboard - Okay.
Loaded pistol in a glove box or armrest - Not Okay (Can't be clearly seen)
Loaded pistol sitting openly on the passenger seat - Okay
If you get stopped with a loaded firerarm in the vehicle, let the LEO's know immediatly on contact with them that there is a loaded gun in the vehicle and where it is, before you begin to move about.
You will probably have the vehicle searched, but no issues if there's not one concealed without the license.
Concealed carry is totally different altogether.