I pull a 16ft Doolittle with a 48 and 54 walk behinds, trimmer, edger, blower, misc tools and stuff. All stop and go in town with a 2001 Dodge 2500 Cummins, Automatic. 4x4 with 33 inch AT tires and I average 15-16 MPG!!! Just under 200,000 miles now and when I need to pull a dump trailer or ANYTHING I can do it. Love the diesel!
As far as "not liking all the stop and go" I rebuilt original starter last year for $36! Took one hour to do.
My truck is FULLY loaded with all options, cost me $10,000 used and is still worth $10,000plus! One thing to consider with diesels is the resale value after 100,000 miles is MUCH higher the ANY gasser.
I do think any 3/4 gas would soot you just fine for that trailer set up. This is just my experience. Good luck.