You can also approach southward through the FFA PvP area if you don't mind, and the previous poster failed to mention you must find the entrance to the cave from the dune sea side.

I have completed a flashpoint with the daily quest, one that I completed previously and don't have an active quest for, picked up the daily the same day, and don't get credit for completing the daily when I complete the Flashpoint. This has happened several times. Anyone else? Forgot the in game knowledge base actually works now, this is a known issue, sorry.