Sins of the Father (Story Mission)
Speak to Virgil after freeing the Hope County Jail, to get this story mission. Alternatively, it seems to auto-populate when this region is liberated.
This one requires a trip out to the Jessop Conservatory, which is also an outpost.
There's a giant rock in the northwest of the compound that makes an ideal place to snipe from, and to hide behind. Use it to clear the resistance, but remember the area, because you'll be back later.
You can search the big house for a local map, and some oregano.
There's also a flamethrower inside, if you want one, but don't have it handy.
Your next goal is to torch the three plot-marked plots of Bliss blossoms. A molotov works as well as a flamethrower.
You may want to start with the plot that doesn't haven't sprinklers going. For the ones that do, look for the nearby shed with the slanted roof, and turn the yellow crank inside to shut off the sprinklers.
Every time you torch a field, another truckload of cultists drives up by that rock in the northwest. It is, of course, easiest to take these guys out while they're still in the truck.
When they're all dead, Feeney himself approaches in a helicopter. You can either take him out here with sniper rifle or rocket, or trail him back to his home base.
That base is up the road north.
Exterminate everyone there. Expect to see six normal hostiles, plus Feeney, whose Bliss consumption has given him an Angelic resistance to damage. Gun him down to complete the mission.
Note that there is a Cheeseburger Bobblehead inside, off the kitchen.
Completing this mission also buffs your Survivor homeopathic.