Well, by the end of 2006 we had towed this combination for almost two years and have gone from sea level to 9500 ft and climbed and descended mountain grades, driven all imaginable kinds of highways and the byways. We hit 110 camping nights this year for that two-year period and about 25,000kms of towing (16,000kms on two trips, one 10K and one 6K on a four week and three week trip respectively and the rest being weekend outings up to five hours away from Ottawa).

We've driven the Canadian freeways and US Interstates with the 18-wheelers up to 70 mph +. We've had a couple of panic stops, one notable one near Scottsbluff NE that required a change of underwear but where the truck, trailer (Hensley, Prodigy) performed as expected. 

We are barely within Toyota's specs on all counts (been on the scales three times) but just about at the GCWR and GVWR of the truck. I spoke to a local Toyota dealer at length about this on more than one occasion and, to summarize, they said no problem. I've even had the trailer at their lot so they could see it all hitched up. No one gasped, and no one flinched. 

In terms of towing such a big trailer, well, I spent a lot of time researching the issue. Fretting, more like it.  I studied this for almost a year and in the end came to the conclusion that power isn't a problem (don't be afraid to use 2nd gear and let it rev) but handling could be a problem.  BTW I found a couple of towing tests during that year and the Toyota 4.7 (at the time) beat out all the other half tons.  I have a lot of faith in that motor even though people say it's small. It may be, but it generates its peak power at reasonable RPMs so the power is easily accessible and the 4.10 gearing is great. How does it handle? We're very happy with it but we've never towed ours without the Hensley and to be honest I'm not interested in trying either! 

Why the Hensley?

I spoke at length with Andy Thomson of Can-Am RV in London, Ontario and he essentially said forget the power, that the Sequoia has plenty, but that as an SUV it doesn't make a particularly good tow vehicle - high centre of gravity, short wheelbase, tires with a lot of sidewall flex, etc. He said it could be set up to be a reasonable tow vehicle if I changed the tires to a narrower tire (he provided specs) and did some hitch mods, etc. He said the other option was to get a Hensley. He had nothing vested in that advice since I wouldn't be buying a trailer or hitch from him, living eight hours away. Since I had been planning on installing JBA headers he said forget that and put the $ into the Hensley instead. We passed through the London area last year on our way to Yellowstone and Colorado so I stopped in and they validated my Hensley setup and welded reinforcing bars to the OEM hitch to take out hitch flex.

I was really anxious over this big sail we'd be pulling and we came to the point where we were willing to try it but said ok, we had to be ready to have to sell the Sequoia and get a bigger truck. We were going to try an Equal-i-zer and then upgrade if needed but felt it wouldn't have much resale value whereas the Hensley would. So in the end we picked up a used HA for $1600US and it has been really great. It needs more maintenance than other hitches but it's time well spent and makes for a much nicer towing experience. We had trips in brutal crosswinds and you can feel the Hensley locking the rig up so it can't sway.

On our recent 6000km trip it was well composed on all the Interstates we travelled in the US, but ... we also took a lot of narrow, winding secondary roads through Kentucky and Tennessee and I did find the rig didn't feel as composed as on the straighter roads. I put new tires on (Bridgestone Revos) and ran them up to 40PSI and that helped.  

For 2007 I put Airlift air bags on the truck and they really stiffen up the back end.   Helps with towing and even non-towing while carrying heavy loads. 

I lost sleep over handling because I wanted to be safe with my family but I didn't want to be forced into getting a "bigger hammer" as is the common solution. The Sequoia is a wonderful all 'round vehicle and towing is only a part of how we use it.

And on the subject of 18-wheelers, we get some push/suck - you can feel it - but we don't get moved around and require only very, very small steering corrections for some trucks, depending on what kind of truck is passing. I've followed other trailers have seen them pushed around where we just cruise along. 

Well that's our long-winded story and experience to date.