sky's the limit here IMO
a cap on a pickup truck and good HD plastic toes that seal tight are what I used for most things, helps keep them from absorbing a lot of scents too and GOOD ones' will keep things dry as well
guns and higher valued items ride in cab with me in good locked cases!

NOW< if looking for ways to lock things up when OUT Hunting and using a truck as a base camp, again, GOOD locks and cases are what I have used , TAKE Pictures of things in there , for insurance reasons if stolen(receipts too)
also a good idea to talk to your insurance agent and ask about how to protect things too and what coverage you have or can add!
good gear adds up FAST in $$$$

I have also had very good luck with Cabela's PVC dry bags, waterproof, and scent free, but do get stiff in COLD weather