Problem is the game wont get any updates anymore aside from maps, so beter dont break our heads for making things better that wont change anymore.
Aside, you do sound as you would need some help on map making, if you do, just ask?
Doing the heigtmap is when you have to draw in 3D case but on 2D paper.
Besides.. layers are helpfull but not a must (in a programm that supports layers, of course).
But without drawing in layers it is a work that needs to be very exact. Every mistake wont be forgiven.
Should there be a Video tutorial showing every thing step by step? Would that be more easy?