Lost Lands of Greyglen

So my question is, do these place-names appear anywhere else, or did Bradon just make them up as he went along?

So, one of the more curious points of QUEST OF THE RIDDLES, the second of the two D&D Kid Stuff recordings from 1984 (a sort of D&D light, with all the role-playing taken out), is the mention of several places that bear no resemblance to any official D&D world I'm aware of. 

Castle Vitalia lay many miles from Stongheart's home, 

through the dark forest of Greyglen, 

across the two rivers of Elfin Valley, and 

high in the rugged mountains of the Copper Dragon. . . . 

After two long nights, the good paladin 

could see the rocky towers of Castle Vitalia 

rising up above the forest threes.

My guess is that they're just made up on the spot, without any authority.

But it'd be nice to know more, if there was more to know.

--John R.