Need help choosing new tow vehicle

For that light of trailer the 3.5 EcoBoost is overkill, I would go with the 2.7 Ecoboost. I think that you would find it to have plenty of power and fuel economy approaching that of the eco diesel. The actual cost per mile of the 2.7 may be less than the eco diesel around here where diesel costs about 15% more than gasoline plus you also need to include the cost of DEF. Of course, that depends on relative fuel costs in your area. I would expect it to be easier to start a gas engine in norther Ontario certain times of the year. The EcoBoost engines run fine on regular gas so use that in your cost comparisons. I have the 3.5 and I tow over 11,000lbs with it with no trouble. From what I have heard the 2.7 is nearly as powerful and gets better fuel economy.