I think you want to start with a general strategy book (be it Kaplan, PR, etc.). You want to have a strategy for attacking questions (especially types that may be unfamiliar to you such as DS) before you use OG and GMAT Prep (limited resources). You'll get a nice math refresher (geometry, number properties, etc.) If you aren't familiar with CR questions, I would assume learning the different CR question types would be helpful (if you have studied for the LSATs before, you probably have a nice head start for CR). A strategy book will also identify some of the more general SC error types on the exam. All-in-all though, I think I definitely got more out of OG and GMAT Prep having a general feel for the exam than I would have had I started with them.

After you get through the strategy, other highly useful resources: Kaplan 800, some of the SC notes on the resources section, Manhattan GMAT SC book, and the BeatTheGMAT Flashcards.