Well, yes, you can take out all of the pages, but they would all be looseleaf, and that would not be so convienent. KWIM?
And, as you are a subscriber to TGM,, I don't know why you would need to take anything other than the maps into the parks. I think the passporting touring information is, well, useless. (Sorry about that, but its JMHO).
All the itinerary planning and touring information you should be taking into the parks should be TGM stuff. Have you seen Stephens Condensed Touring Cards in the forums? Make sure to check them out! For more specific TGM related touring info, better post on the TGM boards as we cant talk about it here.
BTW, lots of people use and recommend Passporters on the TGM forums, and lots of people use/ recommend some of the UG stuff too -- you never get flamed over there for asking about or recommending other sources of information. Its a totally different type of forum because its PRIVATE. I hope you get a chance to surf it!