What is the price range you are looking into?
My vote is for a 2000 to 2002 F-250 with the 7.3L
BTW That 4.7l dodge you drove. hook it to a trailer and it will get 10 MPG or less.
My 7.3 got 13-15 mpg towing. Truck and trailer weighed 15,000lbs that is an in-closed trailer. 18-20 MPG unloaded