This topic isn't a huge focus point of mine. I wont claim to be an expert. That said, I had a hunch that what /u/TacosArePeopleToo for transportation of weapons wasn't something to be taken at face value. While I know California law because I live here, a google search in the 9 minutes I had to wait to post this comment gave me the following:
No federal permit is required. And the Firearms Owners' Protection Act (FOPA) shields you from local restrictions if you're transporting firearms for lawful purposes.
Under FOPA, notwithstanding any state or local law, a person is entitled to transport a firearm from any place where he or she may lawfully possess and carry such firearm to any other place where he or she may lawfully possess and carry it, if the firearm is unloaded and locked out of reach.
http://www.secondcalldefense.org/self-defense-news/traveling-your-gun-legally
One of the law's provisions was that persons traveling from one place to another cannot be incarcerated for a firearms offense in a state that has strict gun control laws if the traveler is just passing through (short stops for food and gas), provided that the firearms and ammunition are not immediately accessible, that the firearms are unloaded and, in the case of a vehicle without a compartment separate from the driver’s compartment, the firearms are located in a locked container.[11]
https://www.law.cornell.edu/uscode/text/18/926A
In most states, firearms may be transported legally if they are unloaded, cased, and locked in the automobile trunk or otherwise inaccessible to the driver or any passenger.
Most states being the keyword. Opposite of /u/TacosArePeopleToo who said "Only a few states require they not be."
If you feel so strongly to dispute me (I'm all ears), then here is a starting resource in the form of a wiki page about US gun laws: https://en.wikipedia.org/wiki/Gun_laws_in_the_United_States_by_state
Note that quite a few states require that guns and ammo be separate from each other.
Oklahoma prohibits the transportation of a loaded handgun, rifle or shotgun in a “landborne” motor vehicle over a public highway or roadway.
Quote: http://smartgunlaws.org/guns-in-vehicles-in-oklahoma/ Source: Okla. Stat. Ann. tit. 21, § 1289.13
Idaho:
However, you must obtain a concealed handgun permit to carry a concealed gun in your vehicle or on (or near) your body, unless you are on your own property, or in your own home or place of business. (Id. Code Ann. § 18-3302(7).)
http://www.criminaldefenselawyer.com/gun-possession-use-laws/Idaho.htm
While you may openly carry a weapon without a permit, Utah requires a concealed carry permit to carry a weapon concealed on (or near) your body or vehicle unless you are in your own residence or on your own property. (Utah Code Ann. § 76-10-511).
http://www.criminaldefenselawyer.com/gun-possession-use-laws/Utah.htm