Clarification on some of the books principles.

Hi all. I've just finished reading Getting Things Done about a week ago, and am starting on my second pass (hitting the main topics) to try and cement these ideas. However, I'm still left with some uncertainties on a few topics. Reading through some past posts cleared a couple up, but there's still some remaining. I'm hoping with the vast experience some of you seem to have, you wouldn't mind helping this amateur out a little bit. ;)

First up: projects. I took David's advice and created a project reference file system. I'm used to planning out projects when I get them, and detailing the steps needed on the road to completion, albeit at usually a broader scale, so I decided to refine this. When processing a project from "in", I plan it out right there, except instead of a broad set of steps, I create a list of narrowly defined next actions, write the first NA on it's proper list in my organizer, and file the project plan. However, from the sounds of it, you can/should only have the current NA for a project on list, but I find that if I'm not at home where my filing is, and I complete the NA, yet have time to do more, how do I know what my next NA is (since I shouldn't be keeping that in my head)? Do you guys take project plans with you in whatever you use to organize things? Do you write down the next few NA's on a list, just incase? I'm probably over-thinking this, I just don't want to become terribly inefficient.

Aw, son of a... I had more questions, but for the life of me I can't remember them at the moment (my memory is terrible. Hence my attempt at GTD :p ). They'll probably come to me in a day or two, so I'll reply again when they pop up.

Thanks for now!