Chest content stealing - What to do about it?

My storage room in the wild is over 1000 DC. I probably have 50+ of stone, 35+ of arrows, and a bunch of other junk. Not that it's super valuable, just would bug me if someone took what belonged to me. Not a huge expense (or time) to build the storage room(s) or the locking doors.

Depends, but my preference would be a simple piston door which can only be opened from the inside.

Same thinking still. Shelluser can relate, I have about 200 chests in my mIn storage. 1 for each item. But also many more for casual dirt, stone, netherack, gravel and some other basic items.
These basic items, I have 1 locked DC and the rest open to the world. If I really care about dirt stacks, I must be a diehard hoarder... I ain't one
..

It sounds like you've got a good plan with your storage room.

If you plan to transition to signs later, this is my current favorite setup, the glass keeps the chests from floating and you can just replace the sand/dirt with a sign if you ever want.