Some small questions that i have on custom scenario

Hello everybody, i'm a noob,for your wise council!

This time i have a question regarding a very cool westeros map called: "Game of thrones new map 2017) that i like because of the right setting/immersity, Tactical places like moat cailin are actually very usefull and not just a reference,...

The only problem is that the map size is ludacris and therefore the primary source of lag in the game (2nd maybe the fact that i play this game on a laptop)

Are there any tricks to have less lag or is this just a curse bound to every ludacris map?

I also wonder if there's any chance of rescaling a map like this to giant? (maybe the most stupid question ever but i'd like to check if this is possible?)

If not... how could i recreate this map as easy as possible? I'm not that good in map building and i have no experience/knowledge of triggers/ scripts/...

Another problem that i'd have is that i'd really like to include the whole north when making this thing... sadly.. when i tried a few times i usually end up using al of the space for all the regions below the North... any tips on how to figure out how not to fuck up your scale every 10 secs?

Sorry if i'm unclear on any of this

Looking forward on answers and gaining knowledge ;)