Treasure Maps (locations and Artillery)

[Quasi 5]

So many of these can be up on cliffs where you spend forever to get to them and cannot get tames to assist with the spawned damned. 

We had a Mastercraft Map recently for example where we spent over an hour sailing to it then many hours (much more than the loot is worth) building multiple ramps and massive ladders to get right up to the highest point on the island where it was.

In this case when we did get there, we built a small fort and mounted a puckle gun and a cannon only to find for some silly reason they did no damage to them.. (apparently related to golden isles having damned pulled to ships and farmed for gold? Making them immune in all locations isn't the answer..)
We did finally manage to kill them all in melee, but took to long to do it i guess, as when we approached the area to dig, another full pack respawned.

Anything that can be done to prevent the spawns from being right on top of pinnacles of mountains and cliffs, or at least making the high level damned kill-able by small (3 man) company i.e. being able to use Artillery would be much appreciated.