At the risk of beating a dead horse, I said I'd elaborate on the milage from a recent 6 week trip to the Canadian Maritimes & Newfoundland. The rig is a 2012, 2350 with all the bells and whistles, no toad, fresh water tank filled as needed. I won't completely describe every stop & fill, but here is a sketch:
Initial trip from Elkhart with STRONG winds & 70-75 MPH - 14.0, 13.6, & 15.6
From home (MD) to Maine - Interstate @ 65-70 mph - 14.0, 15.15.6, 16.5
Trans canada HWY mostly 7 campground- 50-55 mph - 17.9, 17.8
Hwy 1 & 2 - Cabot Trail, HILLS (required down shift) towns & camp - 50-55 mph - 16.6, 15.9, 17.4
Hwy more level, still 50-55 mph - 17.2, 16.6, 17.8, 16.6, 17.9, 17.6, 17.3, 17.2
Hwy - hills, 55-60 - 16.6
Hwy - 55 mostly - 17.5, 16.7, 18.2, 17.5
States - Rt. 1 & towns - 55-60 - 16.4 & 17.1
Interstate to home @ 65 - 16.1
Hope this helps -
Jack