That would definitely set you up for achieving a high score. However, keep in mind that it is more important that you are realistic and use whatever source you decide actively, rather than trying to get through multiple sources. I understand you would like to get a more thorough undertanding of things since you've been out of school for a while, but how long do you plan on studying? Because your plan is very ambitious, not impossible, but here is my suggestion for you:
Go through First Aid first since it is pretty comprehensive and covers everything you need to know in an organized way. Every time you come across a topic that you feel you need more work on, look it up in your old textbook, Wikipedia, and do some decks for it. But if you do this for everything, not only will it be unrealistic for you to retain it all, but it wouldn't be an efficient use of your time. The boards tests at a more basic level than you learned it in school. So I don't necessarily think it's the best use of your time to look back at your books before you have looked at First Aid and gotten a flavor for the level of detail you need to understand things at. Then once you feel that you have covered everything in the First Aid book and supplemented it with other sources, try doing some released exams to see where your weak spots are and go back and fill in the gaps. Then, the last week right before the exam go through several released exams and look up everything you don't know, while committing a lot of the questions and answers to memory (as there are a good number of repeats on the boards). Hope this helps. Good luck!!
