Welcome!!! Glad to have you here.
You’ve got a lot of questions. Let’s try and help you…
Mears is the service. I have not used them, but Disney has new door-to-door comp service from the airport to your room. (There are threads on it somewhere or talk to the person you are booking your trip through.)
Crowd levels. Check this link: http://www.touringplans.com/BestDays.htm
You mentioned the “Official Guide.” To me, the OG reads like a tourist brochure. Everything is fuzzy and happy. You’d think WDW is perfect because they’re talking about themselves. The “UNOFFICIAL Guide to WDW” is the book to go with. It’s comprehensive, easy to read, and (I feel) dead on in its praises and criticisms of WDW.
Pop Century is great! Although the rooms are small, it’s so festive and colorful. Unlike any hotel you’ve stayed at.
Finally, pin trading.
Here’s a thread about ebay: http://www.disneycentral.com/forum/showthread.php?p=243133#post243133
And in the bottom of the forums list, you’ll see a whole section on pin trading.
Hope this helps get you started. If you forget everything else I’ve just typed, remember this: Buy the Unofficial Guide!!!