Pop has 2,88o rooms.
Each of the All Stars has 1,960 rooms with the exception of Music which now has about 1,568 rooms including The 192 family Suites.
Pop was planned to have 2 sections and was supposed to share buses with the 2ed part of Pop.
Bus rides are quite short from the ALL Stars according to PassPorter.com
All Star Buses-CBR buses---POPbuses--PO buses--- Contemporary
MK 20 min---- 20 min-----25 min------10 min---20 min(mono)
Epcot 10 min-- 15 min-----20 min------10 min---15 min
MGM 10 min----12 min-----15 min------15 min---20min
AK 10 min------20min-------15 min----15 min---20 min
DTD 15 min----20 min------20 min-----15 min---35 min
It only takes 10 minutes to get to Epcot, MGM and AK from All Stars.
MK is 20 min away. That's the same amount of time it takes on the monorail from the Contemporary.
A WORD ABOUT BUS SHARING
To me Bus Sharing at the All Stars is really a non issue.
In the mornings during Park opening hours each All Star usually has a dedicated bus.
During mid day it is usually just our stop and maybe one more on the way to the parks. On the way back sometimes it is all 3 but often Sports and Music share and Movies has it's own bus back.
Each of the All Stars usually has it's own dedicated bus back from the MK.
That is a big plus. It seems like the Music bus stop usually has the shortest of the three All Star bus lines.
I guess some people who stay at POP see all 3 All Star names on the return sign of our bus stop when they head to the POP bus stop and think All Stars also has 3 stops on the way to the park.
(Even when we stop at another AS resort to load up it has not taken more than 5 minutes and we are on our way!)
Have fun at Disney!