I found ours on Cars.com and had to drive to Atlanta to get it, a four hour round trip. Broaden your search area and be patient but ready to jump when the right one comes along.
My two cents forgo a 250 for a 350 and if you truelly want a Ford find one with the 6.7 PSD.
2008 GMC Sierra 3500 SLT DRW D/A 4x4 (Big All)
2006 Ford F350 PSD SRW King Ranch 4x4 (Henry) (Sold)
B&W Companion, 90 Aux Fuel Tank, Scan Gauge II, Curt f/m hitch, Swagman XC
2015 Forest River Sierra 360 PDEK
DW Diane, DS Michael, FB Draco and Sabian