Ford Explorer Sport and Small TT

I for one think that would be a good combination. Several years ago I towed a slightly heavier trailer with a Ford Aerostar V6 and it had adequate performance. Your Ecoboost Explorer has over twice the horsepower and will tow that trailer with ease. I wouldn't hesitate to tow it even with the NA V6. As you probably know, the same engine in an F150 can tow 10,000+. Your concerns with payload are valid, but with the proposed trailer weights and what you expect to carry you should be in good shape. With a good WD hitch setup I think your biggest issue will be keeping it under 70 even on the hills. Also, that trailer will definitely have brakes on it as IIRC they are required to be standard on any trailer over 3000K GVWR.