Scout the northern wastes

Scout the northern wastes is an unmarked quest in Fallout, given by High Elder John Maxson of the Brotherhood of Steel.

Quick walkthrough
Locate the Mariposa Military Base and tell John Maxson about the base.

Detailed walkthrough
Initial reports from scouts, as well as the location of the mutant body that Vree recovered, indicates that there's a massive source of super mutants brewing in the northern wasteland. The Elders of the Brotherhood of Steel want the player to verify the rumors.

To complete the quest, the player needs to head northwest of the bunker on the world map. After a few days of travel, the military base will show up. Entering the location is considered scouting.

When the existence of the base is revealed to High Elder Maxson, he convenes with the remaining Elders and the player may attempt to convince the Elders that he requires Brotherhood assistance in storming it.

Rewards
Unusually, the reward is given to the player at the start of the quest. Once Maxson gives the quest, the player needs to ask for an additional weapon. He will then redirect them to Mathia, who will allow the player one of the following:
 * A DKS-501 sniper rifle
 * A Rockwell BigBazooka
 * A Ripper vibroblade
 * A Big Frigger power fist
 * A Wattz 1000 laser pistol