The 1980's and 1990's happened.
Here in my state of Connecticut in about 1984 as a wee little one, I clearly recall that it was common for pickup trucks to legally have rifles/shotguns on the rear window gunrack. It was also common for a used pickup in the classified ad to have options like: New tires, gunrack, winch, plow.
By about 1986 the option "gunrack" was rarely mentioned because you couldn't use it anyway
. Feelgood (to who) legislation hard at work.
Legality implications aside,
may I suggest that one practice how quickly a trunk weapon be acsessed and brought to a readily useable condition? Maybe in a tactical, not legal.
Legality implications respected,
Have 2 or 3 copies of the portion of U.S. General Code that state it should be ok to have a rifle in a case providing that there is no ammunition touching the rifle.
I could not find a Nebraska.gov /DMV/ Highway Patrol/ Legislative site that would return any result for the searched word rifle. It is your butt, so don't take my word for it.
I like 3 AR mags in a toolbox.