Have you weighed the Highlander or just going by mfg specs? When you tow the Highlander, will you put anything in it? You might want to think about a lube pump so that you can tow four-down. Not for me.... but it might work for you.
If you get a very lightweight dolly, you should be ok.
When we were looking for a new toad, the RAV4 and Highlander were 1 and 2 on our list as we are Toyota freaks; but alas, no Toyota is towable four down and I'm not going to put up with a dolly or trailer or do any mods to a brand new car that might jeopardize the warranty. Hence, we chose the GMC Terrain. I was very hesitant to purchase anything other than a Toyota, but I have to admit (surprise, surprise), the Terrain has turned out to be an excellent vehicle.
Ron
Ron & Sandie
2013 Tiffin Phaeton 42LH Cummins ISL 400hp
Toad: 2011 GMC Terrain SLT2
Tow Bar: Sterling AT
Toad Brakes: Unified by U.S. Gear
TPMS: Pressure Pro
Member of: GS, FMCA, Allegro
RETIRED!! How sweet it is....