ALthough I've never used passporter, the Unofficial book is really good as are these boards..You will get an answer for anything you can think of to ask here. On the flip side of the coin, we have stayed on site and personally for us we don't mind staying offsite. It can be just as convenient although you would need to rent a car ( which we prefer over disney transportation any day.) That makes it way more convenient if you want to go offsite for meals, other attractions, shopping, etc...There are some great deals to be had if you spend the time looking.. If money is an issue, you may want to consider this. We personally are park rats (we don't spend much time at all at the hotel) and really can't see the logic of spending $200-300 a night on a hotel (of course our hotel is free but even if we had to pay we'd still stay offsite just for the cost alone.). But if thats your preference, the Disney hotels ARE nice. Just research all you can and then once you have all your info, sit down and come up with a game plan. I agree with another poster that you don't want to "wing" it. As far as attractions for your kids, I would try to let them experience as much as they can and come up with their own dislikes and likes. I think all the rides/shows are great for any age (with a very few exceptions.) thats what makes WDW a truly family destination.!! Have fun planning!!!!
p.s. I know the library should at least have the Unofficial guide, if yours doesn't have the most current edition, then have them check other branches, but honestly if you can get a fairly current one (04-05) MOST of the info is the basically the same (and actually some of the info is exactly verbatim from older (1999-03) versions.