I don't understand why everyone gets so hung up on the whole permit thing. Folks, let me clue you in on a little secret, please.... 1. In about 48 states you don't need a permit to transport your firearm in your vehicle. You don't even need a permit in CA to transport a gun in your vehicle!
2. In many states, you don't need a permit to open carry a loaded gun on your belt, or in your car.
3. Having a permit in your home state is not really required (especially if you are taking advantage of the Federal law).
Here's a couple good resources:
OpenCarry.org - A Right Unexercised is a Right Lost!
You especially want to look at the open carry and transportation maps. Click on an individual state to get a summary for that state.
Handgunlaw.us
Click on a state to get specifics.
You can either transport your firearm in accordance with state laws, or you can choose to follow the one federal law, Firearms Owners Protection Act (FOPA) 18 USC 926a:
United States Code: Title 18,926A. Interstate transportation of firearms | LII / Legal Information Institute
Notice that in the above law, the gun only has to be unloaded and in the trunk. Ammo goes in the trunk with the firearm (just not in the firearm!), NOT separate! If you have the ammo in the passenger compartment, and the gun in the trunk, you have not complied with the above law! The firearm and the ammo can be in the same locked container inside the passenger compartment if you vehicle does not have a trunk.