The problem with the Highlander is that it is built using the same platform as the Toyota Camry sedan. The 4Runner has a truck frame and is better suited to towing.
The lighter trailers use lighter but more expensive materials in their construction. I would opt for a used lightweight trailer over a new one that was 1000 lbs. heavier with a small tow vehicle. The lighter the trailer the more reserve capacity in terms of taking gear along in the trailer or in the car.
Never mentioned but I care about whether if the brakes or brake controller fails when towing a trailer whether the tow vehicle is going to be able to come to a stop in a reasonable amount of time and distance. Even my Tahoe though rated to tow over 7,000 lbs. took forever to bring to a complete stop from 60 MPH when towing a 3000 pound total trailer load.
