On the map on the frontpiece, Thorin's Map, there is a little bowtie at the southern side of the mountain. This represents the door that the dwarves fortified and then lead their assault from. It can be presumed that Thorin would have died not too far south of that point.
Moon Runes are the hidden text on Thorin's ancient dwarven map.
Gandalf only gives Thorin the key and the map (they go together) because they are rightfully his( being given to Gandalf by Thorin's relatives).
Olof Thorin died in 2004.
The moon
Gandalf is worried that Smaug may become an ally to the newly returned Sauron.
Out of Thorin and Co., only Thorin, Fili, and Kili die in the Hobbit.
At the unexpected party, Gandalf gives Thorin a map of the Lonely Mountain, which has information about a secret door and the key to the secret door.
Three dwarves but many unnamed die in the Battle of Five Armies. The three dwarves were Thorin, Fili and Kili. Fili and Kili fell defending Thorin.
There were moon runes in the map. The could only be read by moonlight, and it could be only the moon in the same phase or same night. The runes told how to find the keyhole to the secret passage.
He had to supply the key that came with the map of the Lonely Mountains from the beginning of the book.
Gandalf had met Thorin's father. He gave him a map and a key that his father wanted him to have.
In the Battle of Five Armies