I tow a 184bh with a 2010 Limited - no WDH.
I've never had a problem, even during a 1500km cross country drive. I tend to load up the trailer vice the truck, but I have had the truck loaded on occasion with bikes and firewood. It did feel a tad light in the front end during that trip, but it was relatively short (50km) so I wasn't overly concerned.
I personally think the 4runner is a great TV, except for the idiotic location of the 7 pin connector