About a year ago I installed the 40" snapsafe "underbed" which fits perfectly between the wheel wells of my 4Runner. At the time the best deal was home depot and under $400. I keep the barrel key which is the override on the loop with my ignition key. Easy to conceal the thing in the position it is in.
My deployment concept is if I have to leave with the PDW, it goes in a
generic 21" tan canvas gym bag with a shoulder strap, along with a few other necessities. I am really not a big backpack person although that would also be an option.