It sounds like you're doing great Lisa! With the hopper pass, once you've entered any park it gives you unlimited admission to all four parks for the entire day. So, with a four day hopper, you will be able to come and go between all four parks for your entire four day stay. When you leave a park they will stamp your hand, then when you enter another park you will need your ticket and to show your hand stamp. (You keep your pass.) You can go to the same or different parks, whatever you want. You are going to have such a great time!
I have only been once at the beginning of February and it was not crowded at all, though that has been a long time ago. That's why we chose to go then on this trip, hoping to avoid long lines. From what I've been hearing, for the most part the longest waits we encounter should be only 10-15 minutes. I can live with that! (Heck, we waited 45+ minutes to ride the Exterminator at Kennywood this summer, then it made us all queasy! lol)
You can check out
http://www.touringplans.com/BestDays.htm for the best days to visit each park.
We will be at Epcot on Thursday evening for dinner and Illuminations. On Saturday we're planning on Epcot in the morning, then hopping over to Magic Kingdom for dinner and SpectroMagic/ Wishes. Right now we don't have any parks planned for Friday or Sunday. We'll be there for 10 days though, and with three kids I want to make sure we have some "down time" if needed.
$388 for 4 nights at Pop Century sounds pretty good! It just opened last month, so it should be nice staying in a brand new resort. I've read nothing but good reviews about it, too!
Here's a link to some great pictures if you haven't seen them yet...
http://allearsnet.com/acc/g_pop.htm