with the weight of standard options and battery, it'll weigh around 3000lbs. before cargo, water and propane.
your Highlander has a tow capacity of 3500lbs., IF it has the factory tow package. this includes hitch receiver, tranny cooler, pre-wiring for brake controller and 7-pin connector.
if it doesn't have it, your tow capacity is probably 2000lbs.
you'll easily be at or over the 3500lbs. loaded for camping.
i wouldn't tow a 20' full height TT with it.
a 3500lbs. tow capacity usually means you're limited to popups, teardrops and trailers like the R-Pod.