I'll agree with Overland 4 from Book I, but I'm not a big fan of the Durnore music from Book II. I like Willow and the Light from Book II, which plays at night in Raven's Gate, Port Kuudad, and in Northern Farrock Range.
Does it? In xolotl's editor, every map has two tracks it can play. I don't think that they are dependent of the current time of day (though Willow and the Light fits perfectly with the nights of Port Kuudad).
I always liked Durnore for some reason, don't know why.