Hi to all, it's my first post here.
I've been around for a while and this is great community.
I'd like to get some advices from you, much more experienced cartographers than me.
I am writing a fantasy book with (of course!) a map, and maybe some more maps for different historical periods.
I started with some scratch maps but soon i realized that (especially when my book is read by other ppl) i need quite polished maps to enjoy reading, correcting, and progressing the story itself, because the map is very important and is a consistent part of the (imaginary) world.
Here comes my problem: how can i manage changes in map?
I am using Inkscape because i do not like non-scaling images.
At the moment i am using different layers for:
  • Background (map "paper")
  • Coastal line
  • Mountains, forests and other environmental elements
  • Rivers / lakes
  • Big cities
  • Little cities
  • Cities names
  • Geographical names
  • "Rendering" layers (fog, grass, snow...)

When i need to do some changes in a city name or in the shape of a lake, or i need to put a new lake, my method is ok.
But if i need a new region, or i decide that a kingdom of the map has no sense anymore and i want to delete it, the change affects heavily all layers.
I thought that i could make a layer for each region, with (sub)layers in them...but this means a *lot* of layers (5-10 regions x 5-10 layers... 25-100 layers!) or should i do a different file for each region and assemble them after printing?
What methods do you use to manage this kind of things?
It seems that the problem is even bigger with non-svg softwares, and this is the second reason for which i am using inkscape. Managing a changing and half-finished map in a traditional software as far as i know is almost impossibile, but maybe i am wrong.

Thank you all!