Used DP, Miles vs Years

I would add to the comments that for the most part you will need to expect the unexpected. Low mileage = none of the appliances were used much because the RV set for long periods of time, Or the RV was lived in and the appliances have many hours of use. In the same category you can put the drive line and tires. As most have mentioned maintenance records help, but have a contingency plan with funds to replace items as they go bad. High mileage could mean the same thing or the opposite. Bottom line find one that fits you and be prepared to make it yours by purchasing stuff