Hi and welcome to the group.
I had a ‘99 Mazda B3000 4x4 Crewcab and towed a 2500# popup for a couple of years here in the mountains. I often wished it had the 4L. Up here, you will not see that 21mpg. Maybe on a run down I95 to Florida. Figure on 15 to 17 mpg in town.
You will definitely be slow coming up the Saluda Grade on I26 or up to Black Mountain on I40.
If you find a well maintained Ranger or B4000 with a factory tow package, it should be fine to pull that trailer.
It was 26 degrees this morning. You think you will be warm enough in there?
Enjoy your new toy.
