There have been several of these over time around the world, using old airframes as restaurants. I've even gone to use them myself (who remembers the Constellation at Faro ?). They never seem to last more than a few years. The issues seem to be :
1. The novelty wears off for the local market.
2. Airframe deterioration becomes very expensive to repair, especially something 50 years old to start with.
3. The restricted fuselage size does not suit a restaurant.
If I really wanted to do this (which I don't !) I would consider what the Marriott Hotel at the old Liverpool Airport did for their forecourt with a Dragon Rapide, and have a full-sized authentic-looking model built using appropriate weatherproof non-aviation materials.