Hello Tim,
It is highly likely that some asbestos may have been used especially around the cooker. It may also have been used in some form as wall or roof insulation, or as insulation around any flue pipe if ther is a fire fitted. This is distinctly bad news, as Asbestos is a notifiable hazardous substance, and must be handled and removed by licensed hazardous material removers
Unless you are prepared to spend time, effort and money to have it removed and disposed of correctly, I strongly recommend you don't take on such a caravan..