According to Ford, you should be good to Tow 9700lbs.
Keep in mind, you still need to be aware of tongue weight, and how it affects your payload. But if it is just you and that trailer as you describe, I suspect you can tow this load with no issues.
2015 F150 Lariat SCrew, Shortbed, 2.7L EB, 2wd, 3.73 locking rear, Panoramic Moonroof
2014 F350 Lariat SCrew Shortbed, 4x4, Powerstroke
Previous Truck: 2013 F150 Lariat SCrew MaxTow HD Payload, 4x2, EcoBoost