My 73 Barth Classic has a gas tank vent tube under the dinette seat in the storage area!!!(?) What is up with that? Everytime we stopped, the RV would start to smell of gas fumes. Later we discovered that the blankets we stored in the compartment smelled of gas as well, including the plastic storage bag that held the blankets smelled of gas. Anyone else have this problem and what to do?

It sounds like your tank vent is disconnected from the outside vent. I'm not sure the layout of the early coaches. Some have a tank vent hose that attaches high up on the filler hose, or sometimes to an outside vent. You will definitely want to get that routed outside some how.

Maybe someone with the early style coach could chime in.