My guild decided not to do PTR, because we didn't want to spoil fights.... But I'm rather clueless as to where the raid entrance to Dragon Soul is. A little help here please XD
Go to caverns of time till the central hub where the sleeping dragon is, with all the sand clocks, follow the path right to the mount hyjal raid entrance is, there you'll find some portals, is the second one.
CoT, as you go in it's down the new eastern corridor, second portal.