I posted a question last year about removing tobacco smell and got lots of great suggestions.
Thought I would share my success:
1. My 1977 Starcraft looks too delicate to wash the canvas, so I did not touch it.
2. First we washed all hard surfaces ( floor, ceiling, cabinets, tables, plastic windows ) with a strong detergent mix ( World famous "Al Mix" = HOT water + tide + dish soap + Oxyclean + Amonia).
Lots of work, and the smell remained.
3. Discovered almost all the smell was in the cushions!
Carefully removed the cushion covers ( which are beginning to disintegrate ) and very gently hand washed them in ( WARM Water + Tide + Oxyclean ). Rinse carefully in warm water and line dry. ( The water turned dark orange-brown after two cushions, so I only washed 2 per batch. )
We also washed the seat cushion foam in the same mix, very carefully and rinsed with a hose. ( Too chicken to wash the bed forms) Foam is surprisingly expensive, so be careful with it.
This did the trick! Smell virtually gone, although I store the unit with an air freshener inside to be double safe.