Yes 300 hours is just about right. these were the books I took in with me:
Two three ring binders. Composed of GA Tech material, solved problems, and miscellaneous info I printed from the internet. One of the binders was the GA Tech one. By the time I included all the supplemental info I had to split it in two. GA Tech really gives you a good foundation. It also has a good section on code and NESC.
Camara reference manual along with the associated sample test and solved problems. the reference manual came in handy but I did not really use the other two books.
Graffeo book. Electrical Engineers Guide to Passing the PE Exam. Handy reference manual good and concise. Good lighting and wattmeter info. I recommend a good cursory reading of this book. A nice amount of miscellaneous info which could come in handy. Good section on CT's. also has helpful sample test.
Complex Imaginary sample tests. Good sections on ideal transformers, motors, and code problems. Some problems are on par with actual exam problems.
Spin Up exams. Problems are not as difficult as exam problems but they focus on details which come in handy during exam.
NEC handbook, as opposed to actual NEC book. The additional, clear explanations worked better for me.
Grainger and Stevenson's Power System Analysis. I used it more as moral support than an actual reference.
NESC book. Focus more on NEC as opposed to NESC. I would recommend becoming familiar with the basic goals of NESC and what it covers and doesn't cover. If you read through NESC introduction I think that will be sufficient.
Complex Imaginary NEC drill book. I highly recommend getting this. Time was tight so I only worked through about a third of the book. the drills helped me become familiar with where the topics were located. As I attempted each problem I would underline the nouns in each question. then go to the index, look up the nouns and go from there. You just have to grind it out but if you use that process you should be able to answer the drill problems in 6 minutes or less. I felt really good about the NEC test questions as a result of this book.
As I worked through each sample test, if I couldn't find the answer in my reference book I would google it. I'd then print that info out and add to my notebook. A lot of this included PLC's, VFD's, GFCI's, harmonics, voltage classifications, short circuit calc, generation prime movers, load flows/bus types and any other subject I couldn't find.
NCEES sample test. Good overall study guide. Know different ways that the problems can be asked. I only carried in the 2011 edition but also had 2009. Problems are exactly the same. 2009 contained a lot of general info which is now found on NCEES website. My guess is NCEES wanted to be able to quickly update any rule/guideline changes. If I have to do it again I will spend a little more time on this test.
Finally spin-Up suggested a good test day strategy.
1) Don't skip around the test but go through each problem in order. On first pass, work the ones that you know off the bat and don't necessarily have to dig deep to solve.
2) Mark the NEC/NESC problems with a "2" and work on the second pass. That way you don't have to worry about going back and forth between the code books and other reference matl's.
3) Mark all problems with a "3" that you think you can solve after digging deeper in your reference matl's. Also, any code problems that you couldn't work on the 2nd pass should also be marked with a "3".
4) Mark all problems with a "4" that you really don't know but maybe can use solid engineering reason to solve. Hopefully by this time you only have about 20% of test left. I'm not saying I was fortunate enough to have this happen to me I'm just telling you my strategy.
5) Mark all problems with a "5" that you have no idea how to work. Assuming the light bulb doesn't come on for these, I would recommend doing a quick scan on the rest of your answers, seeing what letter is trending and go with that.
On some of the "4" and "5" the light bulb did come on for me after a 2nd or 3rd look. Hopefully that made up for any careless errors I might have made on 1-3. I actually used that same strategy to pass the CEM (Certified Energy Manager) exam in 2013.
Hopefully all this translates into a passing score but nonetheless I felt really good about my test prep. As a result of my cross referencing and various tabs I was able to quickly access a good amount of info. How you organize your references and sticking to a test strategy are just as important as knowing the material.