I just picked up a PA-108 FAT 50 calibre ammo box
, on sale at Princess Auto, that will fit my MacBook, iPad, several hard drives and other small valuables. Hopefully I can find somewhere out-of-sight to secure it inside the 5.0TA once we get it home. In the meantime I intend to attach a means of locking it and a box-type cover for the lock so it can't be cut off. When I get around to this project I'll be sure to post what I do.
I've looked at lock boxes and fire safes for this purpose but each has more limitations for me than what I decided upon. The ammo box won't be fire-safe but that's a compromise I can live with.
For some camping situations we will likely just leave our electronics at home but for extended trips and other foreseeable uses we will want to have some means of communication &/or music along with us. You must anticipate needing/wanting your equipment along or you wouldn't be asking the question.
Hope this idea helped.