GTD is really more about using your tool as a placeholder to help you remember where you left off in a project--you might find you like it better if you don't try to load up everything you're going to do in every context for the next year into your system. Others may disagree with me, but I keep project plans separate from my system until I'm actually ready to think about DOING those individual tasks.
Hope that helps. And hope you'll treat yourself to that iPad. I never dreamed I'd use it as much as I do or that it would be as cool as it is!