V8 Explorer with HD Tow, or without it? Pretty sure you get 7200 pounds of towing capacity with the HD Tow V8 which will handle any hybrid out there. Check the Ford towing guide for your model year for details (they're on line).
Used campers can be fraught with problems if you don't inspect them ruthlessly.
Not sure what the "read between the lines" comment was about other than folks frequently find small campers just too small and buy bigger. 19 feet gets you a sofa and dinette. Under 19 feet seldom has both making rainy, buggy nights crowded even with children the age of yours.
You should be able to tow a Roo 23SS like ours. Highly recommended. The slide out "doubles" interior space.
-- Chuck