this is my first dually, previous truck was a 2011 f250 CC long bed, same length as my current truck. Yet my current truck having the heavy tow with widetrack front helps the turning to be better than the SRW. parking, I park far away always did, the white whale will fit between the lines in the parking garage at work easily. navigating tight areas you do have to pay more attention to the hips fitting.
Mileage, that will depend on gearing and driving habits, I went from 16.8mpg to the drw getting 15mpg....she isn't a prius.
For each negative item you might find there are 10 positive things that cancel it out once you tow with it!
Yes, ford made a short bed drw years ago, I don't think they or GM does anymore, Ram is the only one that I know of with one.
As for used, when I looked around the only ones in the northeast I could find were prior work trucks.