The materials on the linked page contain spoilers for the module. Probably not killer spoilers, but certainly enough to detract from both your experience and that of your group. You are going to spend 51 time units playing this adventure. nothing on the next pages will increase your chances of "winning" or make your character better. They will help your GM and enhance your game. So, if you are not a GM, please do not read any further.
GM material to help you play RHOD
Look at Wizards' Map Gallery for online versions of the maps, unadapted to living greyhawk
Wizards also provide a Web Enhancement containing the creatures in a handy, downloadable and printable form.
Or just read a WOTC article on the development of RHOD