So, some time since my last post here as I have been a little busy, but now I'm back to work on some projects

Anyway, the thing is that I'm having some trouble while doing a map from my state (RS - Rio Grande do Sul) in Brazil. I need to do some plateaus in the hand drawn style, but I oviously cant use the mountain brushes I've used on my other maps, so I was wondering if you guys could help me, how can I do a group of plateaus (or a REALLY big plateau, as it is almost all the north of my state)?

Thank you for any help and sorry for any english mistake,