I share the OP's concerns.
Hiring a player or player group to provide "security" is a very popular suggested solution. It's a myth, however.
In reality, hiring players to provide security won't be remotely viable for anyone but the largest org's. No player is going to guard your cabin in the woods for an hour or two. Watching paint dry will be a more exciting activity in comparison. And paying that guard would mean at least matching their potential earnings from other game play activities. Not to mention that you'd need 24/7 guards... it's just not going to happen.
You could also cover your cabin in multiple gun turrets, walls, traps, etc. (ruining the aesthetics), but static automated defenses are notoriously unreliable when faced with a patient and inventive aggressor.
The RDMS rules defined in your territory control unit (TCU) will protect your structures from "casual trolls" editing your stuff, but it won't prevent destruction/theft of your stuff. But TCU's are supposed to be expensive and hard to build, so they might not even be a practical solution for solo players or even small groups, especially in the early months after launch.
Your best bet is to join a reasonably large player org and build within the "safety" of their guns and defenses.
However, it's impossible to predict the risks in DU at this early stage of development. Much of the detail has not been finalised yet. It sounds like there will be a relatively high "opportunity cost" to everything in DU. Casual trolling for lulz may even turn out to be a very costly hobby.