Just drove from Huntington,WV to Lunenburg, VT via Johnstown, PA with my car at max towing capacity with the back of the car loaded also. Rolled over 250,000 during the 1,000 mile trip.
On the trailer are: three portable toolboxes, a set of wheels, a log splitter, a Subaru EJ22 engine, a tuff box full of tools and car parts and another tuff box full of personal items. The previous owner put big (for a trailer) 205/70R14 tires on the trailer so it rides nicely.
I crossed the Alleghenies, Poconos, Taconics, Catskills, and Greens mountain regions on the way up. The kicker? I still averaged 21 mpg while maintaining the speed limit.
Right before the trip I changes the timing belt and pulleys, water pump, cleaned the injectors, replace all lateral link bushings and hardware, and replaced the differential outrigger bushings.