Help, please...newbie towing with a 2011 Toyota Highlander

I would limit the dry weight of the trailer to be about 3500 lbs. at most. then when you lightly pack it, add some water, etc. will be under 5,000 lbs.
check out the Ascend line, they have several units that would work for you. much more liveable than a Casita which I looked at one time, stopped by the factory but the bath was too tight for me. also little storage.
an Aliner would also work for a low profile with no canvas to worry about.
bumpy