The following are changes to caves for Miami 50x are vanilla, without mods. The structures in place are indestructible, and are to be treated as an actual terrain wall, any meshing or mesh attacking is prohibited.
VALGUERO
ALPHA TREE
(COORDS: LAT 42 - LON 75.1)
Main entrance.
Other alternate entrances blocked.
QUAD WATERFALL CAVE
(COORDS: LAT 33.5 - LON 10.4)
All other entrances blocked. 
This water hole blocked. Only 1 water hole remain as main entrance.
CASTLE CAVE
(COORDS: LAT 40 - LON 90)
Main entrance lowered.
Second entrance blocked.