Would it be completely ridiculous to suggest not having the guns in the vehicle? I have no idea whether you're allowed to ship weapons so this might be a stupid thing to ask.
It would for a wide variety of reasons. Cost effectiveness for one. Maintaining positive control of your personal arms for two.
The cost is the worst part. It's extremely expensive to ship firearms via a freight shipper. For one they have to go from FFL (Federal Firearms License, commonly used to indicate an individual who has such a license) to FFL. So I can't ship them myself, I have to turn them over to a third party, who ships them to a fourth party. I then have to go to the fourth party and PAY for my property again. Because I have to do another background check and do another form 4473 (firearms transfer, in this case of my property from the FFL to me), and I'm pretty sure you need to do a form 4473 for each firearm. Now some FFLs will be cool about that, and only charge you one background check fee and one transfer fee, but there's plenty that will charge you an individual transfer fee for each weapon. At $25-50 a weapon that adds up very quickly. $200-400 for the transfer fees + Background Check Fee ($25-$35) and shipping costs $40-50 per rifle and you're very, very quickly in the thousands of dollars. Would you be willing to do that for some of your personal property? Things you've already paid for?
The ridiculous part is that it shouldn't matter if I have the guns in the car or not. As long as they're stowed properly (and mine always are) which is to say in a locked case, separate from ammunition, as long as my weapons are legal in my point of origin, and legal in my destination then Federal law protects, or should protect, me and my property because I'm in transit using the Federal highway system. Certain states like New York, Illinois and New Jersey are however determined to fleece more money off of people, and like most cops, steal their property as well, so you get the usual corruption run around.