I like to have two locations. One is a strongbox, which is intended for papers, prescription medications, external USB hard drives, and if big enough, the laptop itself. The goal is to resist a smash and grab. As of now, I use a metal box that uses a steel cables looped through the backseat, but I eventually want to get a "Dorm Safe" from Dean Safe in my next rig which is a lot better.
The second location is someplace out of the way, mainly intended for spare keys. I don't like diversion safes, since it is likely those would get chucked out, or forgotten. There is always the Hitch Safe which is a small compartment which goes into the tow hitch and has a cap on it. This is good enough to stash a small key or two. This way, the chance of winding up locked out of one's rig is minimized.
Then, there is the safe that gets put into use if going for a long trip where one's wallet and keys are not needed. Attach the Mesa MHK1 Travel Hitch Safe to the tow hitch with a decent locking hitch pin, toss ones stuff into that, call it done. It won't ward off someone going at it with power tools, but it will keep one's keys and such safe while hiking.
