How to read a travel guide? Well lets say, read the "about" chapters of the country such as history and cultural introductions plus some of the regions, where you have been traveling?
The history and cultural description chapters to the country, in this case The Philippines, do give quite a good understanding in the people and live. It creates a bigger relation between the traveler and the country he/she is visiting. Thus it gives a deeper interest and experience throughout the journey I believe.
For the particular locations, you should take them as rough guides but not as plan. Do not follow strictly this book, nor carry it all the time along the way. Better, find yourself a few ideas and goals, very you are heading to but then, alter your journey on the way and make it your own experience, the book can not give you anyway. It is important to aim for a goal to make you moving, not to achieve the exact same one.
The book itself, even though very profound, can neither be complete nor up-to-date, even if you purchased the newest edition. Beware of this and don't start with wrong expectations.
Enjoy the Philippines.
* (have been traveling to Palawan and Coron)