Hoppus and I took a break from development during the holiday pause but we've touched on many of the big gameplay aspects thus far so the rest of the development for GCWIII should be pretty smooth. I'd say 2 months is a best-case scenario if we wanted to launch ASAP, but it's probably going to be closer to 4 months before we're finished. Dementat is currently building the Death Star III in-game, and the due date for that thing is mid-May... which will force GCWII to move into an Endgame scenario wether we like it or not, so that is the "due date" for Hoppus and I to be done, as we'd like to transition into GCWIII with as little delay as possible.
That gives you plenty of time to get involved in GCWII if you felt so inclined, even if it was purely for storyline purposes.