In general, assume that normal DragonQuest, Third Edition rules apply, except where noted in these web pages I've constructed below.
Name Generator for selected cultures
These external links can give us some background info on the setting. Let me know if you've got others.
Ardalambion - the tongues of Middle Earth
The Encyclopedia of Arda - reference info on many aspects of Middle Earth
Latitudes and Longitudes - someone's attempt to compute latitudes and longitudes for Middle Earth
Questions and Answers - about Tolkien's works, from Green Books
River systems - a fishing guide for Middle Earth (odd, huh?), but it describes the river systems
Weapons and Armor - recreations from the LotR movies