Here's my recommendation for DM scroll farming.
Have each person in the party make a map of the mine so that they know where each room number is located, which ones have two rooms, where the exit portal sends you, and how many docs & keys are in each room.
In large parties (4-6) have one person be the coordinator. That person does not look for keys or documents. Instead they check rooms that have been done, assign new rooms to people as they finish, collect keys & docs from people as they pass by, send the keys with someone to the chest in rm 16-5, and answer questions in case anyone has some (like telling people how many keys & docs in a room, etc). Everyone reports on party chat what is going on, but one person is keeping track. A good location for this person is between the npc and the bottom right where chests send people out of a room.
In small parties (2-3) it works best to assign rooms to certian people (this can be done a veriety of ways) and have each person aquire everything from their assigned rooms. Then when each is close to finishing they can check with the others to see where they should go to help.