I would go ahead and bite the bullet and take EC's, you can study the same way as you have for the NC tests.
But remember, you dont have to have all your requirements done before you are able to schedule for the CPNE, you have to be (please correct me someone if I am wrong

) 10 or so credits away from being done. But you do have to have all the nursing concept exams done.
I will have to take several general requirements when I
schedule the CPNE, but during the long wait, I plan to take any remaining exams. (so maybe you can hold off on the A & P until later and just concentrate on Nursing concepts)
I hope that helps!!!!
Lisa B