HePFAP will not work at the lower limits, the opponents are too dumb for you to outplay them. What you need to do is have them outplay themselves. You are coorect in realizing that you should never bluff, esp at the lower limits, you will just get called down.

For NL, HePFAP wont relaly help you, that book is based solely on mid and upper LIMIT holdem. NL = different beast.