Yep. I'm not going to drag 50 N frames to Oklahoma! Many places and opportunites for those gems to be stolen...from your vehicle while at a motel, to in the venue itself apparently!
35+ years working gun shows here.
The only time a gun was stolen from my FFL boss was by a night security guy. All one has to do is run a small, plastic coated cable through the trigger guards. Use short length (say 3') so you can unlock the cable & pull the gun loose should you need to show it. Loop each end of the cable so as to provide a secure point for the locking device. Wants to see another gun? Then lock the first one back up & proceed to the next one.
Wire cable can't be broken with bare hands.
Theft resistant isn't brain surgery, gents. It can be done quickly & affordably.
As for the motels, just take the guns into the room when one stops for the night. Use basic non-marked boxes to hide what's in them. Maybe go through a drive-thru for you food, so you don't have to go back out to eat.