I have completed the Lion's Landing introductory quests as well as two sets of dailies on the PTR. I got the quest from Sully McLeary to go to the Horde base in Kun-Lai Summit and sneak items away from Garrosh. Then, the quest completion text said something like "Meet me at Headquarters to continue".
There was no follow-up quest offered and any possible "Headquarters" (Shrine, SI:7, Lion's Landing) do not have any quests for me related to this storyline either.
How do you get to the Dalaran storyline, then? Or is it just not yet implemented on the PTR?