Lucky me, I popped onto the PTR today just as they were doing a 10 minute countdown to a server shutdown. Undaunted, I portaled out to the Isle of the Thunder King to see if I could learn anything of value. I arrived to a small camp very much under construction, with half naked dwarves hammering away. Piles of boxes are laying around and a handful of NPCs have daily quests for you. I did not have a chance to do any of these daily quests.
Another thing I noticed is that the NPCs here are from the Kirin Tor and Silver Covenant (I'm going to assume that Horde have a separate hub elsewhere). I'll have to complete some of the dailies to see whether we will indeed be working with Kirin Tor/Silver Covenant rep. The patch notes read that there will be a new Kirin Tor variant for this content, but who knows? There is also an NPC at the camp labeled as a "Silver Covenant Quartermaster". At this time I am unable to interact with him/her.
The official patch notes say that you can choose PVE or PVP for these quests, but my hunter was flagged as soon as she zoned in. I'm not sure exactly how this PVE/PVP thing is supposed to work, but I may learn more as I do the dailies.
As yet, no sign of the great forge! However, I see that the latest patch notes indicate a new recipe for "lightning steel" which also works as a discovery recipe. I can't wait to try that out! There are also a few new Tailoring recipes and a change to Imperial Silk that allows it to unlock discoveries as well. Should be some interesting information to uncover there :)
** UPDATE ** Got back onto the PTR tonight and was able to finish one daily quest. So far there are seven dailies available, most don't seem to be working. The one quest I did complete gave me (prepare yourselves) "5.2 Alliance" rep. So it seems that it will not be an existing faction. Also, the whole zone is PVP flagged and I could not figure out a way to get around that. After getting pounced twice by evil Hordies, I gave up researching for the day.
Feel free to leave any questions you might have about 5.2 professions in the Comments!