It was mentioned in the sidequest that the Fiends main base in Vault 3 was infiltrated by a Ranger who they had lost contact with and you were tasked to find if you had the chance while you were there killing the Fiends boss. I *think* I checked every inch of the Vault twice over and have yet to find this guy. I had let go a group of prisoners but none of them looked like a Ranger, and none of them identified themselves as such, so I have to assume he's still MIA.

Has anyone else found this guy? And if so, where?

Yeah I found him. Hes sorta near the entrance of the vault. It was awhile ago so I don't really remember. But when you set off two land mines you know your getting close. PS Have the medical kit because he wounded.

Ya, hes behind a hidden wall, like the one in 101 but on the opposite side.
I believe you have to go to where the captives are, then while facing the cage door turn 180 degrees and go down and up the left hall.
He should be behind the door.

What are the options for this quest? You bluff your way into vault 3, get to the leader motor-runner, then you can make a deal with him. If you pay him, he gives you his helmet and I guess that's that. If you decide to fight him, when you kill him it says, Quest Failed: Abba Dabba Honeymoon. So I'm wandering what that is about. I checked my pip-boy and it doesnt show any info on failed quests, so I'm just wondering if I missed out on something by fighting him.

I found the ranger in this quest and went after hunting motor head. The ranger died on the way up. Does anyone know what happens if he lives?