Múspelsheimur isn't a hill, it's another world. I would not call that close enough
But they're still coming out to fight
Oh and don't forget the most important event of Ragnarok, when the Midgard serpent Jormundgandr fight Thor and both are killed. Sounds pretty similar to Alduin versus the Dragonborn and his Dragonshouts.
Actually there is just one myth, it's called V?luspá and it's an ancient Icelandic poem. A poem I've read multiple times.
What about the Edda? I'm not sure myself, but if V?luspá is the only poem about ragnarok then I assume that it's a specific part of the general Edda?
Edit: nevermind, figured it out
http://en.wikipedia.org/wiki/Voluspa