I have not had much experience with 800Score - did not realize they had one. We keep a list of those and reviews here:
gmat-prep-courses-classes-reviews-ratings-and-comparison-78451.htmlYou don't need to cover both Kaplan and Princeton - just one book is enough. Technically you should not need to cover a prep class and then Kaplan or Princeton. The prep course should be enough in itself. If you re doing both, may skip the class if you still have an option.
About the rest, many people here use specialized
Manhattan GMAT books for RC, CR, SC or Powerscore series
Manhattan RC
Manhattan CR/ Powerscore CR
Manhattan SC/ Powerscore SC
There are also many specialized books for math.
Have you taken a practice test such as GMATPrep? It is hard to evaluate the Plan if your current level is unknown.