Pop Century will NOT be sharing with any other resort. Why? Because it has so many rooms, it will be crowded enough on its own. The only reason buses make multiple stops is because a resort does not create enough demand to warrant it's own bus. (It has NOTHING to do with Value/Moderate/Deluxe) Pop Century will be the equivilent of All-Star Movies plus half of Music when it first opens, and the equivilent of all three All-Stars when complete. My guess is that when it's complete, there will be two separate buses for it (Classic and Legendary) similar to how there are three separate buses for the All-Stars at times. (Sports, Music, Movies)
As for location, Pop Century is in a great location. Approximate travel times:
Magic Kingdom: 12 minutes
Epcot: 7 minutes
Studios: 5 minutes
Animal Kingdom: 5 minutes (12 mins with stop at BB)
Downtown Disney: 12 minutes
Blizzard Beach: 7 minutes
I haven't heard, but I'm thinking there might be a possibility that Blizzard Beach gets a figure 8 similar to how the All-Stars gets. Currently that route runs DAK -> ASR -> BB -> ASR -> DAK. However, it is possible that it will be BB/AK like other resorts.