This horde cave is located southeast of Crazy Willies in the same area where you followed a Nero helicopter earlier in the game, at night they gather around a mass grave site about half way between the cave and Crazy Willies, directly north of the cave.
This horde can be taken out during the day or night, if you decide to do it at night there are bushes around the mass grave that you can stage your attack from, but there will be more Freakers out besides the horde.
I did this mission during the day, there is small rock ledge to the right of the cave with a bush back a little from the front. I used an attractor to lure them out of their cave and took them out with molotovs and pipe bombs, I used a total of 6 molotovs and 2 pipe bombs. It’s definitely easier during the day.
This mission pays 2000XP, 1200 credits, 1550 in trust points, and the Horde Killer story line will be udated.
Thanks for watching, God Bless and happy gaming.