When I considered getting an enclosed 6x12 v-nose trailer to haul my bikes to track days and what not, I drove and sampled a buddy's trailer first. I had just installed the 1 inch front leveling kit and hooked up the trailer semi- empty. Weight was around 1500 lbs.
To be blunt, with the front level kit, it sagged a lot in the rear and you could feel the 4runner struggling and I did a 30 minute or so highway test ga400 North with some rolling long hills around 65mph. It didnt feel good and being very gentle it was averaging 9.5 mpg.

I installed some air lift air bags, went back to test the same setup again and the sag ALMOST went away completely, it felt much better and didn't struggle nearly as bad and I averaged 14 mpg replicating the same test from last time.

I went and picked up my own 6x12 and have used it to haul 2 bikes and all kinds of stuff in the trailer numerous times. Probably around 2500 lbs.
Last 250 mile trip I made with this configuration (airbags) to Alabama, I saw 13.5-14 mpg.

If you're gonna tow with it, especially above 1000 lbs, I HIGHLY recommend getting air bags to help. They make an immesne difference. The V6 really will start to struggle around 3000lbs+, though. Above that, I'd want a V8 and a longer wheelbase.

I've been towing with it from 140k miles to now - around 185k and it hasn't seen any problems from towing. They oem radiator finally sprung a big leak at 180k, but it's a 4runner and I don't think hauling 2500 ish lbs is going hurt it more than it will be naturally hurting itself.

First time trying to tow without airbags vs after






Air Bags top
Without on bottom
(not a huge diff in photos but huge diff in real life)

I have a gen 4 V8 T4R and I pull a 2300 lb. boat on a regular hitch and I get about 13-14 mpg at 70, depending on headwinds. I also tow a 6500 lb. Airstream. No airbags, just a WD hitch. With the Airstream it's just 9-11 mpg at 70 mph, maybe 12 mpg with a tailwind.

For leveling I'd rather use a WD hitch. Airbags will level and get the nose out of the wind but it doesn't change the amount of weight on the rear axle. My V8 4X4 is rated for 700 lbs on the hitch (including hitch). A WD hitch will move some of that weight onto the front axle to get the nose down and some back onto the trailer. The result is a level rig.

I've pulled the Airstream all over the US and I've been very pleased with the way it handles. The X-REAS shocks must play a big part in that handling. I've never had a problem, even with sudden shifts to avoid being hit by someone coming into my lane or with strong crosswinds.

Attached Images

 

Is that a 19' Airstream? I want one of those so bad...

It's a 2006 23' Safari SE Anniversary Edition
The double axle starts at 23' but there are a few 22' with double axle. It varies by year

Attached Images

       

Just completed a multi-trip move from FL to TX, towed my cargo trailer with my 300k+ mileage 4Runner both times, hauling furniture the 1st time and 4 motorcycles the 2nd. Trailer itself is approximately 900# empty. Not a worry, rig handled it with no problems.

This article by people who tow a travel trailer with their 4th Gen V6 is a good read.

Nice! Thanks for the pics! Love it. I was always skeptical that my 4runner would be able to tow that. So, thanks for the info.

Hopefully you got the towing package. Among other things, it has the connector for the brake controller hidden behind the driver's kick panel. Get the Tekonsha brake controller (I have the P3) and it's just plug 'n play. Fully integrated into your 7-pin umbilical plug.

The package has the needed frame hitch, tranny cooler, larger alternator etc. I use an Equalizer weight distributing hitch, which does a very nice job of leveling and distributing the weight.

You can always get your T4R modified if you want to go bigger. Here's a link to a guy's 2011 V6 Sienna that tows a 28' Airstream International
The Toadmobile - THE TOADS OF TOWED HAUL

He's an interesting fellow with a lot of information about his rig on the site

Here's a pic from his site that leads to more pics.
Galleries - THE TOADS OF TOWED HAUL

Attached Images

 

I tow with my V6 2WD just fine.



I'm not sure exactly what this home-built trailer weight, but being all heavy steel I'm sure it's at least 2,000lb, and the Corolla on top of it is another 2,200. Add in an interior packed full of tools, spare parts, and camping supplies and you have a VERY loaded-down vehicle. However the V6 handles it just fine. I leave it in 4th and have to get a running start to go up some hills but overall it's just fine and it still gets 14mpg while hauling. All the mods I have done are to make it a better towing/camping vehicle.

Frame-mounted hitch
Trailer brake controller
Transmission cooler
AirLift rear helper airbags
Bilstein 4600 shocks
Goodridge stainless brake lines
Motul RBF600 brake fluid
PowerStop Z76 heavy-duty brake pads
Limited model "13WH" front brake conversion
CSF aluminum radiator

The average weight of a tear drop trailer is varies quite a bit from 500 to 3200lbs.

If it’s closer to 3200 and at least over 1500lbs, , I’d definitely invest in a transmission cooler first if it’s a v6, then Airbags to help with MPG. Airbags helped me tremendously with stability and MPG. My 2wd v8 can can get up to 17mpg towing my 1850lbs dual axle trail without anything on it, and that includes going over big mountain passes. Loaded up between 4000 and 5000 lbs it’s more like 12 to 14mpg

The trans cooler will help give you peace of mind when you are going up big passes in summer driving conditions. Keeping up on the trans maintenance and following a severe duty maintenance schedule depending on how many miles and trips you are taking a year. Also make sure the cooling system is up to par.

This is the most I ever towed with my truck, as we made a big move in 2020. Towed in 100 plus degree weather over 150 miles. The 3600lbs Lexus was loaded up with personal belongings as well as the truck, on top of the 1850lbs car hauler. Probably just over 10,000 in gross vehicle weight and payload. You can see the rear squat is almost none existent with the air bags!

Attached Images

 

To add to willissauce said, for stability, consider using polyurethane bushing on the Panhard bar. That will keep the rear of the truck more stable while controlling the heavy load behind. That was one of my pet peeves having the ass end of the truck feel like the tires were flat and one of my first mods.

Kept may Daystar rear lift in mine and took out the front.
I tow a 13 foot 2k lb trailer full time with my 2005 v6.

I have a $100 brake controller and new radiator and fluid swap before I did anything.

I will go back to 265 65 17 tires next time because I lost torque at 55mph in 5th gear and it seems to hunt in headwinds or slight hills.

18mpg in the Rockies, and average 14 or 15 in the plains and east coast.

Attached Images

 

Hopefully not too late to ask for advice in this thread vs starting a new one.
Vehicle is 2004 4Runner SE V8 4WD and it has the OEM heavy-duty hitch. I'm original owner.

Currently has an Icon lift. I had the Icon Overland 2-stage rear springs but replaced them with the less-stiff Icon 2" rear springs. I want to buy a Casita trailer.

My question is, for towing, would I be better off to go back to the Icon OVerland springs for their higher capacity, to offset the tongue weight, or keep my Icon "regular" 2" rear springs and add airbags?

Also, please recommend me a brake controller. An '06 4Runner V8 2WD that I also own, bought used, had one installed by prior owner, but I removed it. Has brake controller technology changed much the past 15 yrs to where I shouldn't consider just using that one?

TIY for any advice offered.

I pull a 6500 lb. Airstream and the 4Runner handles well. I still have the X-REAS shocks which are great for handling. Air bags do nothing for you in the way of support. You don't say what the size/weight of the Casista is. I use an Equalizer weight distributing, anti-sway hitch. It keeps my rig level. In the driver's kick panel there should be a connector for the brake controller (since you have the OEM frame hitch I assume you got the towing package). I use a Tekonsha Prodigy P2. Check their website if you're looking for something more current.

Attached Images