Hi, my DS and DD have taken and passed the history and psychology CLEP exams so I may be able to help.
They used REA , REA crash course, and Princeton AP US history book which were helpful. They watched a couple of movies on the Hippocampus history site also. They already had 2 years of US and world history using mystory of history audio CD and story of the world. We have Tindall and Shea though they did not use it much.
There is a website Clepprep that is very helpful and has well layed out lesson plans. There is a yahoo group attached too. HTH.