EU+ Remastered

I'm thinking of making an EU+ remastered map that includes the same borders and countries as the current one but with some additional cities and minor tweaks.

What is the best way to approach this? I have previously tried cloning the world map but it doesn't run as smooth as the current EU+ does. Add to that I'll have to disable all the other countries one by one and even then they'll be completely blacked out rather than greyed out as is the case with the default map.

Is there a way to get a hold of the exact EU+ map we play by default with the option to edit the cities and costs in it?

If not what is the best alternative to get as close to the default one as possible?

You can't. Only way is to clone world map and disable countries 1by1, no other way around.