Based on this image it appears that each station will require a transfer to a separate line. I think it will be the following routes:
Pop Century to Caribbean Beach
Caribbean Beach to Hollywood Studios
Caribbean Beach to Riviera
Riviera to Epcot
The only line that may be continuous is the Caribbean Beach to Riviera to Epcot but I doubt that will be the case but time will tell.
Although this breakdown would require multiple transfers for a lot of destinations. That could get annoying...especially with young kids and strollers. Hopefully Disney has thought the guest flow through thoroughly and has a good plan!
I wonder how long the lines will be at the end of the day at Epcot and Hollywood Studios, especially since essentially 4 resorts are cramming into a single line to begin with? Capacity should be decent but how many guests can fit in a gondola, 6-8? Will multiple families share gondolas to maximize capacity? Hopefully they will still provide bus transportation to these resorts as an alternative.