Gandalf is a freaking wizard. How could he not have gotten them through somehow? And why did Gimili act like the mountain itself hated them? Was there some sort of supernatural power like Sauron, Saruman, or even the Balrog blocking their way? Gandalf even made some comment that the malice of Sauron was behind the impassable pass. More to the point, why not take the Misty Mountains pass that Bilbo and the Dwarves took? It was right next to Rivendale.