Did lords ever have land holdings that were split up and far apart? I always assumed this is something that would naturally happen over time, yet in Westeros we’ve never hear of it. How would this be managed?

In fact, it was way more common historically-speaking for nobles to have land holdings that were dotted all over the place rather than contiguous, but GRRM didn’t want this to happen because it would make things complicated so he just decided it wouldn’t happen.