Jumping Ship (Story Mission)
Speak to Pastor Jerome after completing The Good Samaritan and entering the final bit of John's Resistance meter to begin this story mission. It's highly recommended you bring along Boomer or a Gun For Hire with the Spotter ability. This also a pretty big fight- a rocket launcher and a good assault rifle can be handy.
Head to the Silver Lake Trailer Park (where Merle Briggs lives), to find it already crawling with opposition.
There are about five enemies to clear, though some may spawn oddly.
When they're down, talk to the resistance leader at your plot marker.
A tide of cultists will start to sweep in from the north. The very first wave will drive up, making the rocket launcher useful but most of the others will be on foot.
The goal is to protect the defector, so you can play this safe à la Wingman and just stay in the trailer, punching out anyone who steps inside.
This does tend to get your companions killed, however, so you might also consider making quick circuits around the trailer, picking off hostiles and reviving friendlies.
As the siege intensifies, the attackers will start chucking smoke grenades left and right. This actually helps you more than it helps them, especially if you have that companion Spotter perk. Just remember, counter-intuitively enough, that the parts of the body you can see clearly are behind cover, the un-highlighted parts are the vulnerable ones.
After the smoke-wielders are down, look for a wave from the south. This one is also spearheaded by vehicles, and thus especially vulnerable to rockets and other explosives.
Defeat this wave and you'll get word that the Resistance is ready to help you by the docks to the east. Enemies will continue to pour in from the south, so grab your guy, and sneak through the trailer park, trying to keep on the north side of obstructions.
You can expect a few cultists to be in the woods between the park and dock, but they're single searchers, not an ambush. Take them out with your sidearm, or your companions' help.
The dock is guarded by armed Resistance members, so make a point of not shooting them. Instead, drop your cargo in the back of the boat, then pick off any hostiles still in the area.
This completes the mission.