I have been anticipating (dreading?) this for a while now. Today was the big day, I towed the boat from Fort Worth to Hot Springs, a little over 350 miles. Toyota got the gearing pretty much right on this one, I might go a little lower on the rear gear, but not much.
I towed in 3rd gear (4spd auto) at 65-67 mph.
No problems on any hills on the interstate.
I was able to run in cruise control, but I would shut it off on long uphill stretches so it wouldn't downshift to 2nd.
I averaged 16.7 mpg for the trip.
Once I got off the interstate in Arkansas, I had some steeper hills to contend with. No problem, I was going slower now, max of 60 mph and other than being slow to accelerate, no problems at all.
All my worries about the 4 cylinder Taco were over nothing, it did great.