What can our Kia Sorento tow?

The kind of body style (SUV, Minivan etc) has little to nothing to do with the tow rating. It's all about what the manufacturer will guarantee the vehicle to tow and that's where they set the tow rating. In MOST cases this rating is for a completely empty car/SUV/Truck etc. This means driver only, no other passengers and no cargo. Weight of any of those items reduces the tow rating. One other thing to keep in mind is the brochure weights on many trailers show empty weight (UVW) and nobody tows around a completely empty trailer. Those numbers have little to do with safety however, they are warranty matters. The numbers you need be within for safety are the GVWR of the tow vehicle which would be the ACTUAL weight when loaded for travel plus the tongue weight of the fully loaded trailer (again, not empty weight). I personally think you're asking too much of an "at best" barely adequate vehicle. Mountains only make matters worse.
Good luck with your decision / Skip