If you get an Acadia, make sure you get the FACTORY TOW PACKAGE no matter what the salesman tells you. You cannot add an aftermarket tow package and get the 5200 lb tow capacity. You will be stuck at 2000lbs without it.
Nothing wrong with the Costco tent trailer. You could put a porta-potty in there if needed, but with a shower, you will need a way to collect the shower water if you are in a developed campground. If you plan on going of the grid, boondocking, then you could put up a pop up shower tent or changing room tent (Amazon) on the outside and have whichever kind of portable shower unit you choose... sun powered heat or electric.
However, the Costco tent trailers are expensive for what you get, and the reviews are mixed. For $2400 + tax, you could get a decent popup camper ready to go. Spend a little more $3-4000 and you can get a nice one. And the resale value of the camper will hold much better than the Costco. Besides, what's the fun if you don't jump in head first?;)
