In our experience and opinion, the Toyota 4Runner is more than adequate to pull the 17' SD. You may recall that the recommended towing weight
is no more than 75% of your tow vehicle's maximum tow rating. On the 4Runner, the max rating is 5000 lbs; 75% of that is 3700 lbs. The Casita
17' is rated for a maximum of 3500 lbs --- 250 lbs less than your Toyota's maxium.
We will be picking up a 2008 Casita
17' SD this October 22 in Rice, and towing it home with a 1997 Toyota 4Runner. We will have installed a WDH hitch (Draw-Tite, 2-torsion bars) and a Sway-Bar that Casita will install. We know from experience that we will have no difficulties towing with the Toyota because between December 2003 and October 2004, we towed a Wilderness UltraLite trailer behind our 1997 Toyota 4Runner across the U.S. The trailer and its contents weighed between 3650 and 3675 lbs (I weighed EVERY item we placed in it and checked the final weight
on each axle
on a scale). We towed it up the steep mountain that separates Jackson Hole from Grand Targee and across the flatlands of Oklahoma. We went up very steep hills rather slowly at that weight
, and always switched to 2nd gear when going down steep hills. Our experience was that others on the road were patient and courteous, particularly as we pulled over whenever we could.
We would suggest that you install a WDH hitch both to ensure that the trailer and the Toyota operate as a single unit (this is a primary advantage of a WDH) and to distribute the weight over the axles for better tow vehicle performance.
If you have not already made a choice about a brake controller, we would like to suggest that you consider the Jordan Ultima; it enables you to increase/decrease the extent to which the trailer brakes
are engaged as a function of how hard you brake your tow vehicle.
Again, if you have not already done so, you will need to have a transmission cooler installed in your Toyota 4Runner.
By restricting our speed to 55 to 65 mph, we found that our mpg was not significantly more than it was without the trailer.
Our Toyota is now in its 10th year and is in astoundingly excellent condition. We have chosen to buy the Casita to a large extent because we don't want to replace our Toyota.