2wd would be best for your mileage towing, I think they are 4:88 gears were our 4wd was 5:13. You will be gear bound with a 4wd, 70 while towing with our LLY we was about 2800 rpms if I remember right and 4wd with 19.5s barely got us out of wet grass. If your mainly highway i'ld lean towards a...