OK, so I had no trouble believing Mullet Head's story right up until this episode. I just figured him for some idiot savant type - with him saying he is from Houston, and with our huge medical center, that was not a stretch for me. Lots of incredibly smart people wander around down there with their fly unzipped. He does seem MacGyver-esque at times, and the water hose thing was brilliant - and also one of the coolest scenes they've done in a while in terms of dealing with a herd. So mullet and country accent aside, I didn't have a problem with it.
What tipped me at the beginning of this episode was the thing about missiles and deployment and "It's classified".
And yeah, not sure what the Sarge does now. Getting to DC was his reason for living. Without a mission, he's lost.