Linda, you'll be arriving at Pop Century on the coat tails of my vacation! We love staying at Pop Century for the decor, the newness of the resort and the value pricing. And you're right, the resort is huge, with 2,880 rooms!
We always request to stay in the 50s, 60s or 70s building. These three "decades" are in a very advantageous position at the resort. They are located closest to the main building, which you'll go through each time you want to visit the food court, gift shop or take the Disney Transportation system. In addition, the 50s, 60s and 70s buildings are closest to our favorite pool at the resort, the Hippy Dippy Pool. We also request to have a room on the ground floor, so we don't have to wait for an elevator or hoof it on the stairs when we're in a hurry to get to a park!
Now for a slight disclaimer, but I'll end with some helpful advice: Room preferences are never guaranteed. That being said, the awesome cast members at the resort have always made our requests happen! If you have an existing reservation, call (407) 939-7675 to have the room request added to your reservation. Then, to play it extra safe, 48-72 hours prior to arrival, call the Pop Century resort at (407) 938-4000 to confirm your request.
In terms of crowd levels, you'll be arriving during the "regular" season, which is a time when the weather is ideal and the crowd levels are much more tolerable than previous weeks (Easter, spring breaks, etc.) To make the most out of each day, visit TouringPlans.com. Be sure to check out its crowd calendar, which recommends parks to visit and parks to avoid each day of the year.