The castle appears on the top of a mountain, a giant structure on the tippy-top of a giant mass of rock. Everyone can see it. Hell, it's probably viable from space.
Plainly, if Dracula isn't going to use it, someone else will see it and put it to good use. Actually, I think that was the plot of a couple of Castlevania games...
 
    

When evil spreads across the land, and darkness rises and the monsters roam. When the creatures of the night make beautiful music, and the things that go bump in the night go bump with greater enthusiasm. When the world is in peril and is in need of a hero...

These guys are, sadly, the best the world can hope for. These are the adventures of the heroes of CVRPG. They mean well, they try hard, and occasionally they do the impossible...

They actually do something heroic.