Tow ratings are figured differently among different vehicles and manufacturers. Some vehicles come with ample support for the rated tow, and some have no reasonable way to achieve the rated tow numbers without emptying the gas tank and hiring a racehorse jockey to do the camping for you. A 6000# tow rating that makes you subtract the 1000# you're going to put in the tow vehicle can be the same thing as a 5000# tow rating that really means you can tow a 5000# trailer.
The very first thing I would do is carefully read the Ford towing information on the website, check the Explorer owner's manual section about towing, and read the driver's side doorpost stickers. I would value actual owner experience very highly.
Ratings are guidelines. Safety is caused by cautious and attentive towing practices, not by ratings or sales brochures.
A TrailManor has less wind resistance than the conceptual trailer the manufacturer is rating, and the low center of gravity makes it much more stable on the road. Most people who own TrailManors use tow vehicles with no more than 5000# ratings:
http://www.trailmanor.com/WebDocs/Ca...-vehicles.html
Violating ratings can have warranty implications, and a fair amount of the vehicle manufacturer rating process is about marketing things like the potential warranty costs of failed transmissions (there's no safety concept associated with the rear axle ratio that improves a vehicle's tow rating).
Your trailer will weigh less if you don't haul 400# of water around.
Some have been concerned over the last 20 years about unibody vehicles being able to provide suitable trailer hitch mounts. But so far, these fears have not been substantiated in practice, and so far they exist only on message boards in the minds of the owners of light trucks whose frame rails have been getting lighter over the years, too. Unibodies are here to stay because they provide greater strength with less weight, and the new Ford Explorer is a good example of how towing an RV trailer is changing.