Thanks guys!

I think the picture itself doesn't need much more improvement. Next step will be adding a legend and description of the outpost. I think about a design similar to an old schoolbook or information paper.
@ Map Vandal: good objection. As the outpost is from a magic-using environment I will assign some defense/structural improvement attribute to the buttresses. But even if this would not the case, I think the angle is quite steep, I'm not sure if this would be useful for climbing up the wall.