I would guess its value around $8-10K if it is clean and rust free. People need to remember, they don`t make them anymore, they have become a niche vehicle. The ones that are being built with new SD`s are going for $80-90k! So $10k for a nice clean truck is very affordable. Definitely sell outright.
My buddy sold his 05 Eddie Bauer V-10 with 40k miles for $26k this spring. the RV dealer that he bought his MH from offered him $15k. He sat on it for a while before selling it. When he did list he got a lot of calls and sold it in 2 months for what he listed it for!