So there are quite a few ghosts in Harry Potter, but none of them seem to go anywhere exotic. They mostly hang around familiar places or decide to haunt some building (the Hogwarts ghosts "haunt" Hogwarts).
Is this because they can't go anywhere strange, because they don't want to, or because we don't hear about the ones that do?
In various fictional settings there are different rules. Sometimes, it's "a ghost can only go where they've been while alive." Is this true in Harry Potter?
If not, are there any other limitations? Could a ghost float to the core of the Earth? Into outer space? To infinity, and beyond?