💙Ok, that actually got use thinking. There are a few ways to go about it.
First question: do you care at all, even a little bit, about writing military fantasy?
If you don't care, then everything about the military aspect doesn't matter and you can do whatever the hell you want.
Woeful_Imp
Westeros is way too fucking big, the timelines are all fucked, logistics don't really make a lot of sense, armies teleport all over the place (this, I believe, is more of an issue in the show than the books, though.)