The only problem is Kosovo...

So, feedback about this would be welcome.

Your problem is obvious: you're trying to pretend that Kosovo is not part of Serbia. The fantasy country of Kosovo the Americans have imposed didn't exist until very recently. Your trying to put it in a map of the Yugoslav ...

Well, sure, Zzyzx is a very cool name. But it's like calling the Gulf of Mexico "Drilling Platform #47;" it's extremely obscure and not representative of the region overall. And it'll elicit a lot of "wth is that?", even from 90% of Californians. If we're shooting for accuracy, of course, the area ...

You might also consider Modoc instead of Lassen for the northeast corner territory. Mt. Lassen is well to the west of there. That area is both Modoc County and, geographically, the Modoc Plateau. Calling it Modoc would also be a nod to one of CA's native tribes.

Cascades would be a better ...

Good looking map and represents my state well. I'd only suggest that Zzyzx is an EXTREMELY tiny and obscure place. How about Mojave, Joshua Tree, or Fort Irwin as the name for that region? (most of that area IS Fort Irwin, which is why it's a big blank on maps)