Invisible walls on private WOW server?

I have an idea for a niche, micro private server that takes place entirely inside Old Hilsbrad Foothills, but a potential issue is that the zone has a number of invisible walls that make access to large portions of the map impossible (or really hard).

Is it technically possible to remove the invisible walls without requiring a custom patch? Can it be somehow done on the server side entirely? (I guess you could also just make the walls walk-through instead of actually removing them etc.)

also hello wowservers, long time no see, how are you guys I’m restarting the bloog soon-ish (?)

PS: I think attempting to host the next big fresh server to rule them all is so 2015, we must move on to niche servers. Look at Turtle WoW, look at Smolderforge, look at Henhouse, Retro WoW etc.ΕΎ

PPS: Another maybe better idea is to have a server inside Culling of Stratholme instance BUT this has both invisible walls and the FOG. Would it be possible to remove the FOG? (The zone would server really well for a sort of a “ok lich king has been defeated and Stratholme partially rebuilt, but the scourge still lingers in parts of our lands and u must kill them !!! because if you look at the entire zone you will actually see actual scourge structures.)