When I sell my vehicles I have a folder that has all the service records and receipts pertaining to the vehicle and this covers oil changes, filter changes, ATF changes, wheel rotations, repairs, and items I have purchased like a car cover or seat covers or shocks or sway bar. I also include a sheet that has my maintenance log of mileage when work was done on the vehicle. For a $50,000 car or truck I find this worth my time. If I was dealing with a lawnmower then I would not bother.
If I am paying tens of thousands of dollars for a used car and truck I prefer to go with private parties who have the service records for the vehicle. If they have neglected the maintenance then I am more likely to get stuck with the tab for engine or transmission or other repairs.
The V-8 engine adds $1500 to $1700 to the price of a truck and so I would expect the resale to be higher than for a truck with the V-6. A crew cab adds more than $2600 to the price for a truck as even the bucket seats on a crew cab cost $500 more than on a quad cab - go figure.
Where I live 95% of the trucks that the dealers order are crew cabs. It is part due to the much higher profit for the dealer and partly the demand for the crew cabs. I know many contractors who buy crew cabs so they can take their guys to a job and so they can use the truck on the weekends and on vacations for their family. I prefer the quad cab to get the shorter wheelbase and overall length, but even the few that are on dealers' lots tend to have the short 5'7" box and so I will need to special order truck.