Likely too much trailer for your Expy. You’ll exceed your payload rating once loaded and add tongue weight and probably your tow rating too. For 2013 your tow rating was calculated with 150lbs in the expy for driver weight. Anything else added to the vehicle above that reduces the tow rating pound for pound. Don’t forget that those kids aren’t going to get any smaller either.
A few hundred pounds over GVWR isn’t going to kill anything but be sure to stay under the tire and axle ratings if you do tow it. I don’t think you’ll be happy though pulling nearly 9k with the 5.4l.
