finally ran numbers. 9.8 mpg out of the truck on this trip, 9.4 worst (much of Canada, 73-75mph), 10.6 best (home to NH, steady 65).
old truck was doing 11.5-13.5 with the camper.
new truck did 11.4 running around town between when I bought it and the start of the trip. old truck would have been 14-15.
slightly disappointing & just about exactly as expected. dashboard is optimistic by 0.3 to 1.5mpg. Have not gotten over 500 miles on a tank yet.
Almost time for oil change and fuel filter.