I had a Leer camper shell on my '00 Silverado Z85 4x4 that had double latches (one per side). It was color matched by Leer when I ordered it, and I loved it. People used to think my truck was a Suburban, it matched the body lines so well.
I had the truck bed sprayed with Rhino liner, and the camper shell protected it from UV sun damage - it always looked brand new. I also owned a Tahoe (wife's ride) but the truck was much more utilitarian. I could haul my dogs in the back (screen windows in full-length sliders) and I had a sliding rear window so I could induce cold air conditioning to the dogs on hot days, which they really enjoyed.
My wife and I, and three German Shepherds, could all sleep inside if the weather got bad; otherwise, the dogs slept by the truck, and we used to camp anywhere with that setup.
Secure? Heck no - what car or truck is?
I used Rubbermaid's excellent Action Packers (latchable and lockable) to carry gear, food, guns & ammo, fishing poles, tents, etc., and you can remove them once you get home, or to your destination. They keep your belongings out of sight, and if you have a locking tailgate, the large ones cannot be yanked out the tailgate glass or side windows, so it does deter thieves. My truck never got broken into, but a lot of effort to park smart and empty the bed at night helped with that, I'm sure.
The Rhino liner was great - haul the nasty stuff, or if the dogs had a little, ahem, accident, then just hose the bed out on a slight slope, wash it down with a brush and car wash soap, and you are good as new.
Tow a trailer and even better, pitch a tent and it rains - truck is instant weatherproof shelter.
Take it hunting or fishing, sleep in it, and greet the sunrise ready to go....
To me, a good truck with a quality camper shell/cap is a superb bug-out vehicle.
Get the Leer and rock on!