So I have a good RL friend that is going to start a new account and toon today. I want to take him to Forbidden reach to farm the 385 gear ASAP. Does he need to finish the entire quest line of DF first? Could he go to Forbidden Reach, gear up, and then do DF questlines?
As soon as he reaches lvl 70, he will be able to go there. The quest should pop up shortly after dinging. Though it may take a trip to valdrakken or a relog in order for it to show up, sometimes these things happen.