Mapping isn't that difficult. If you can tell me what needs to be done, I'll give a shot.
- Seems like terrain and climate are set up and working.
- Rivers are done, too.
- You still need
- a bunch of provinces
- troops and resources
- the towns set up with buildings and population size
Creating provinces is simple, armies and towns can be tricky.
For provinces, resources, army size and composition I'd need instructions and support on the history of that time (really not my field of expertise).
A possible issue is that I won't be able to handle files in anything else but English. Google does a decent job in translating into understandable English, if you don't have English copies or someone willing to translate.
I might not be able to complete the whole thing, but I could give you something to work on.
EDIT: Thanks for the link for that cool map. Quite amazing.
I just miss a legend for all those colours...