as we're playing a 2D game what about a watch tower with "raised cover chance with on tile" only accessible via a "ladder"
T T
U L
a 2x2 structure. if destroyed spawn rubble, dirt and wood?
T = "raised" tiles only accessed via "L" tile
L = ladder, no stopping on as only a transit tile.
U = non-accessible tile to allow "T-L" only access.