I think part of the issue is try to buy to RV of their dreams first time. We had a drop in camper several years ago and enjoyed both with and without the kids.
When time came to see if we still would enjoy camping and a 5er we bought a "Desposable" 5th wheel! It was a 1986 King of the Road. Got it for $1,500 and put about $1,500 in to repairs and upgrades. We enjoyed that 5er for three years before we bought the current rig. We sold it for $3,000, about break even, if I could have only gotten $1,500 would not have mattered we got our money's worth and learned what we wanted/needed and are very happy with the new rig!