Hello, We currently tow an M22 with a 2010 Honda Pilot (Max tow rating of 4500 lbs) and it does a decent job of towing 90% of the time, although I wouldn't feel comfortable taking our set up into any mountainous areas. I definitely feel the lack of power/torque on the steeper grades. I believe the Highlander has a similar tow rating as our honda. As others have mentioned, the weight distributing hitch is a must and a sway control bar will give you a bit if extra security (I was a towing newbie when we purchased our M22 so I needed all the help I could get). The extras do add up..the dry weight on ours is supposed to be 3690 lbs.. but with propane, battery, extra options, and a minimal amount of gear we weigh in at 4,090 lbs ( I weighed the M22 disconnected at a truck stop weigh scale). That being said we never travel with our freshwater tank full and dieting is encouraged around our house ;-)