A few more numbers:
Trip length was 1,201 miles, first 800 miles with tires or dolly as cargo produced 8.5 mpg.
Last 400 miles with laundry trailer as shown above, produced 7.7 mpg.
Burned 110 gallons of biodiesel/veggie mix and 37 gallons of diesel for the trip.
With the fuel selector valve working well this time, I was able to switch between diesel and bio at any time. Interestingly, diesel imediately increased the boost by 2 to 3 psi and the EGT increased
to 1,150 °F. BUT there was no actual change in performance, perhaps a better MPG, but wouldn't know with the information at hand.
The bikini top did well in the heat, but it was still unacceptably hot in the cab. Measured an air temp of 110 °F with an ambient of 95-100 °. Drank at least a gallon of water a day, still got dehydrated.
Removed the custom radiator cover for the return trip to keep the engine operating temp below 200 °F.
Another interesting tidbit, with some of my tires balding and some almost new (laundry trailer), the temperature of the new tires (including my decent front tires) got almost too hot to touch, while the "balding" tires remained fairly cool. The movement of the large rubber cleats must generate a lot of heat...
Driving speed with the laundry trailer was 50-55 mph. Kept 33 mph in fourth gear going up I-77 from NC into VA, a 7-8 mile long 5% incline.