As to the practical aspects: Locked up the longarms in a weatherproof steel case, chained and centered it in the middle of my pickup bed, covered it with lots of other stuff, and most importantly I think, did not drive like an idiot. Thus I avoided giving the constabulary a reason to bother me. Made sure all my lights were working, signaled properly, stayed out of dubious areas, etc. OK, I speeded a bit, but not any faster than the traffic around me.
I do recall that on all my trips, the section of I-40 between Memphis and Little Rock was crawling with troopers from both states, especially right at the state line on the Tennessee side. Good place to make sure your driving performance is squeaky clean.
Good luck.
elb