I have a 17 Limited.

I'm looking at travel trailers...3700-4200 lbs....some single axle, the nicer ones are double axle.

2024 Winnebago Micro Minnie 1800BH for sale in Tampa, FL | Lazydays

I've towed 6x12 UHauls loaded up, but I have no idea what they weighed and I never had an issue.

Look in your owners manual for max towing weight. If the loaded trailer is less than that, you will be OK.

For something that heavy, you should consider getting a trailer brake controller. Fortunately the 4Runner comes with a plug in trailer brake wiring harness, which makes it super easy to add the controller. For new 4Runners, the wiring harness is in the glove box, but if yours is missing you can get them on line.

For reference, 6x12 cargo Uhaul's are ~2000 lbs empty.

Will it physically pull it -- YES
Will it pull it well -------- NO
Will it physically stop it - YES
Will it stop it well -------- NO

A trailer that size is nothing huge in the world of travel trailers, but its tall, big, wide, and has a huge wind drag. That trailer is more than double the surface area of the 4runner, so if its windy its going to drag you from one lane into the opposite lane. Passing 18wheelers at speed, or having one of them pass you at speed it will suck you over into the lane with them. When you have a trailer that the side profile is double what your vehicle is, the trailer is going to start to steer the vehicle in any windy situation. Plus the 4runner is nowhere near as wide as that trailer, your mirrors wont be able to see around it behind you without extensions.
With a trailer brake controller, yes you can drive it and stop it. You will lose a considerable amount of speed on any incline on the highway, expect to hit hills at 65 and the trans downshift 3 gears and be screaming and only doing 50-55 up the top of the hill. The wind resistance and overall weight make that trailer quite the pull for a 4runner. Yes it will do it, No it wont like it.
Also to note the tongue weight. The 4runner isnt exactly the best suited for a heavy tongue weight vehicle, mine squats considerably with 1000 pounds of tongue weight which is likely what that trailer is going to have. Your headlights are going to be pointing at the sky and the rear suspension bottomed out. I have upgraded Eibach rear springs because i tow with my 4runner pretty frequently. I have a 14ft aluminum trailer and haul 2 ATVs as well as a tandem axle enclosed trailer. I have a 7x14ft V-nose tandem axle trailer with 5'5" interior height so the trailer isnt very high, but its definitely noticable behind me. You are looking at a 8.5x21 trailer that is sitting 9ft in the air, that is a WHOLE LOT of wind resistance. Yes it will pull it, but dont expect it to be fun or pleasant on the highway. You will need to learn to hold both hands on the steering wheel and brace the steering wheel with your knee when you see an 18 wheeler coming to keep the 4runner from steering itself into the wind draft.

The general rule of thumb is to not exceed 75% of the towing capacity of the vehicle. Runners have 5000 lb towing capacity and 75% is 3750. I tow a 3000 +/- Casita travel trailer and my runner does well, even on the 8% upgrades in WY & CO. I also have an Anderson Weight Distribution Hitch which levels out the runner and puts weight on the front axle. Food for thought.

Expect transmission problems in your future.

haha, this is exactly what I was thinking the answer might be, damn!! The 4Runner is not the right vehicle for this, even though I could do it and live to tell.

I had a buddy suggest a Casita, might have to start looking at those. And thanks, will look into that Anderson hitch.

I have a 2012 that I have towed a micro Minnie with multiple times. The brake for sure helps as does the weight distribution bars. I have only gone as far as Gainesville ( my older son goes to UF. Soo we use it for the football games.. coming from Central Fl. Soo not many hills until we get up there.

I pull my Nautique occasionally which is around 5,500-6,000lbs with the double axle trailer (under 30 mile trips). The trailer has electronic brakes and the boat is aerodynamic but I still absolutely HATE pulling with the 4runner. I would be looking at a new tow vehicle if I had to tow this boat more than a couple times a year on short trips.

We have over 200K miles on two 5th Gen 4Runners towing a 5000 lb (scale verified) Boat & trailer over the last ten years. (160K miles on a 2012, and 60K miles on our 2020.) We keep under 65 MPH, we tow in Florida, (Flat). We average 11 MPG when towing and have not towed more than 400 Miles in a single day. Other than flat tire(s), we have had zero issues with to towing that weight. I agree that “windage” on a boat is a lot less than a box trailer. Does it perform like a 3/4 ton diesel when towing? Absolutely not. But if you are sensible, it will get the job done without risking engine, transmission etc. You must have trailer brakes by law in many states towing that weight. We are on two axles with disk brakes on both axles.

We tow an RPOD 192 with our 23 ORP. The trailer is a single axle and 3400# dry weight. We have the weight distribution hitch, air bags and brake controller.

Like others have said, yes it tows it but if it hits ANY incline or head wind the 4runner starts hating life.

I honestly think with the hitch, air bags and brake controller it pulls and travels really well. It's happiest at 60-65mph. The biggest problem is that it is so under powered. It's always needing to down shift and it gets really annoying on long trips. You can't really use cruise control much at all.

If we plan on camping within 1-3 hours of where were live we will use the 4runner to pull it because of the comfort and ability to use it to explore around where we camp. If we go further or know it will be hilly I will pull it with the 2500 diesel truck.