Need help resolving a ranch quest bug

Hey guys;

I ran into a bit of a problem with a ranch quest - it worked well for the 2x4, blanket and nail parts, but now that it’s come to salt - on accepting the mission I get a “can’t find ranch_camp_46” message and the wood wall around the foreman disappears! I’m not sure if this could cause any more trouble in the future so I’d like to avoid it, if possible.

I’m thinking the bug probably happens because of the craters nearby, so I want to know - is there a way to replace those overmap tiles with something else, and how would I go about this?