There aren't any hills that are significantly higher than USH if I'm not mistaken, so I doubt you'd see any of them from WWOHP. I know you can see them from other areas of the park, but I don't think you'll see any towering hills over Hogwarts.
And they've moved the entrance multiple times throughout the park's history, so it's not out of the question. But with the new Tour Sign, and the new tour bathroom, I doubt it'll be moved now.