You are in the same quandary as a friend of mine. He wanted a small RV and had a Jeep Liberty that limited his towing to 5000 lbs. No problem, right? He could buy a small RV at around 3000 lbs empty - hard sides, single axle, hard sides, toilet and kitchen - but once loaded it was pushing 4500 lbs. Water and gear are heavy.
The Liberty could pull it BUT only got 21 mpg highway. It needed every bit of the V6 power it had to pull the trailer but that hurts mileage.
Lesson 1: like others here suggest, trailer weights grow faster than you think and Lesson 2: the ability to tow 3000 lbs will hurt your mileage
But an article that is right in your wheelhouse is here:
Yes it talks about 2017 vehicles but many have been around a while, like the Ford Escape.or Subaru Forester.or Mazda CX-9. Note that none of them cracks the 30 mpg point for highway mpg’s.