I'll vote for the mighty inline Cummins wrapped in a Ram. Not sure what your budget is but I'd buy the latest model year you can afford. The 2010 and on trucks (4th gen) are pretty decent. Find the cleanest one you can with little to no rust. Once it's in your possession replace all the fluids', filter's and belt. After that Fluid Film the heck out of the undercarriage being sure to get inside the frame and rocker panels to preserve that metal for as long as possible. Then take real good care of it because the big 3 no longer offer a manual transmission so this rig's got to last you for a long time.
Also FWIW, I owned a 2008 F-350 and occasionally drive a 2009 F-350 at work and those truck drive horribly compared to both my previous 2004 Ram 2500 and 2010 Ram 2500. My current 2015 Power Wagon blows them all away but it has a different suspension set up so not a fair comparison.
Also FWIW, I owned a 2008 F-350 and occasionally drive a 2009 F-350 at work and those truck drive horribly compared to both my previous 2004 Ram 2500 and 2010 Ram 2500. My current 2015 Power Wagon blows them all away but it has a different suspension set up so not a fair comparison.