I had an 03 4-runner SR5 for a while with the V8, and towed a 7500+ Lb trailer from the Jersey Shore to Bloomsburg, Pa. Big hills on route 80 by flatlander standards, but nothing like out west. I also towed 5-6000 lb trailers from time to time with it. I only used weight distribution, no sway control, and a Tekonsha brake control using the factory harness.
I was impressed by the ability of a "smallish" truck to tow that weight so well. No sway, smooth power, stopped straight and safely. I was not fatigued more than usual, and the power mirrors needed no extensions (for me, anyways.) The seats that year were poor, but better than the Tacoma I have now (an '03.)
The truck was bone stock, except the Toyota weight distributing hitch.
Fuel mileage was not so good, towing or not, but it still got better MPG towing than my 454 powered GMC ever did empty. More importantly, I never worried about making it home. :Mechanic:
Check out the frame design on the 4-runner vs, the Jeep. My 4-runner felt very solid on the road. :REExeSquatsHL1: I have no idea how the Jeep is put together, and have nothing to say, good or bad about the Jeep model you are considering.
I was told a while back the 4runner 4.7 was not the same block/engine as the Tundra 4.7, but but was the "Lexus motor." I think this is the first I've heard them compared as above. Not that it matters, both are strong Toyotas. I'm still curious, though...just not enough to look it up!
Edit...
OK, I looked it up...Tundra has an i-force engine, cast iron block, 4-runner has a different designation, not an i-force.