Hi Kevin,
Love Pop Century! The preferred rooms are in the '50s, '60s and '70s buildings, closest to the Hippy Dippy Pool and Classic Hall, home of the food court, gift shop, registration desk and bus stops. So by being preferred, you already have assured yourself convenience to everything you will need.
My family has stayed at Pop Century at least 20 times since it opened, and the '50s section is our favorite. But if you want to be closest to the Hippy Dippy Pool, you will want to ask for the '60s section. You can specify whether you want to face the pool or not.
You can make note of your special room request -- including preferences for ground floor vs. upper floors -- on your reservation when you do your online check-in. There's no guarantee that the resort can honor your request, but I've always found that they do everything they can to accommodate.
Here's the link to the
Pop Century map if that helps you as you make your decision.
I hope that helps. Please let me know if I can answer other questions about Pop Century or the rest of Walt Disney World as you get ready for your visit. Enjoy!
Wilma