2002 Newmar Dutchstar any good

Average mileage for that unit is 11,666 per year. A diesel is only good if it is being driven otherwise it is of no more value than a gasoline sitting in a RV park. What is important for usage when not being driven is the house, utilities and appliances. Newmar makes top line houses but they do not make the appliances and chassis. The appliances are 14 years if they have not been replaced.

For his money he would do better with a later model park model, 5th wheel or gasoline class A. Get newer appliances.