If Magic Kingdom is still open for any reason, (even if it's a private party and you don't have tickets, you can still take a boat there) then take the boat to Magic Kingdom, then a bus to Pop Century.
If Epcot or the Studios is still open, then go to the Outpost bus stop and take a bus to Epcot or the Studios, then take a bus to POP.
If all the parks are closed, then go to the Outpost bus stop and take a bus to Downtown Disney, then take a bus to POP.
If you don't want to fool with riding to DTD, then get to the Outpost Reception area and have them call you a cab.