It SOUNDS as if this is a used vehicle which means you probably have no actual warranty concerns. This being the case, from a SAFETY standpoint what you need to watch is the GVWR of the Explorer. Make sure that when it's fully loaded as it would be for towing, you have enough payload available (difference between actual weight and GVWR) to handle the fully loaded tongue weight. Tongue weights are variable in nature as they change based on how the trailer is loaded. They generally range from a low of 10% and high of 15% of the actual weight of the trailer. I would recommend you base decisions on the 15% of GVWR so you're figuring in the heaviest it will be.
For information about the actual factory assigned tow rating, Ford should be able to furnish you with this information based on your VIN. It is different based on how your vehicle is equipped. Lower gearing gets higher tow rating etc.
Good luck with your RV selection / Skip