I recently worked on an abused 85 Schwinn Traveler for a nephew. It was ridden hard and crashed several times. Mismatched wheels and a modern rd on a bent hanger amongst other crash damage. The hanger was drilled out for some reason and there was a flange type nut securing the derailleur. It went halfway or a bit more into the dropout from the wheel side and had a hex nut protrusion of perhaps 2-3mm extending towards the freewheel. I aligned the dropout and secured this setup with loctite. It seems good to go and a handy little problem solver. I should have taken pics, but it was a bit ugly for this crowd.