For you though it would be - Personal region inside a Town region inside a Kingdom region..
Must have perms to all three to build.
Good way to stay safe. Until TNT is re-enabled.
If it happens, then further precautions would be needed.
for instance, make the walls of your personal region 3 blocks think, and make the center block water. The water will stop the TNT from damaging the inner walls and will keep your goods safe.
Lots of tricks to use IF they ever enabled block damage.