I have towed a toy box trailer, fully loaded, approx 7,000 pounds with my F150 many times over the continental divide, and on many paved and gravel roads thru the mountains. At least 5K miles towing this. I have a 2011 F150 w/ a 5.0 engine.
The key to towing is not just driving safely under the conditions, but having quality equipment. My trailer has 225/75/15 load range G all steel radials ( dual axle) ( my 2 axle car hauler, that I tow my tractor with, has the same) and I use an EZ lift load stabilization system on the hitch. Tow ball SHANK size matters as well. Carrying weight is rated on shank size, not just tow ball size. I also always use appropriate air in the load leveling air bags on my truck.
By using this type of equipment, I can safely tow up to the maximum capabilities of my pickup.
Here’s the problem many people run into while towing. A standard 7K trailer, a harbor freight tow ball rated at 3,500 lbs. original load range B or C tires. Right there you should only tow a couple quads. Not a tractor, not a car, or travel trailer.
What is your life worth? How about the family’s in vehicles around you? An F150 is a great tow vehicle, and with quality equipment, you can tow the legal limit down the highway safely. It’s done all the time. Towing with minimum quality equipment, limits your towing capabilities to maybe HALF or less. I’ll get off my soapbox, but look at your equipment, and drive like your towing, that makes a world of difference.