Most conventional residential cabinets have a fiber board carcass, some still have plywood. The face frame and doors are wood.
RV's are built of less quality with carcass being also fiber or particle board but the face frames on most are wrapped vinyl over the same. Doors are a mixture.
I'm guessing the material cost difference at the suppliers plant would be less than $1K. Assuming you could recover some of the cost by selling brand new RV cabinets, installing better quality residential cabinets might run $3K, depending on count and what needs to be dealt with in terms of mechanicals.
