camsdad,
I bought a used 2x4, 2005 dodge diesel with 40K miles 2 years ago.
its been a great truck, but was a bit more money than maybe you are up for.
I have a trailer about the same as yours and my dodge diesel handles it fine,
plus, it drives and rides good, gets very good fuel mileage, pulling the trailer and just driving around without a load.
has the quad cab, so there is plenty of room inside the cab.
if you do not need the 4x4, you can get a 2x4 somewhat cheaper and not have all those expensive 4x4 parts wearing out on you even though you are not using them, most 4x4's do not have lock out hubs.
good luck and take your time,
as other have said, the ford 6.0 maybe one to steer clear.