We pulled our Jayco 25RKS with our F150 (Large V8, tow package, heavy duty shocks, Rees dual cam weight distribution hitch with anti-sway, Tekonsha Prodigy P2 brake controller, Aux transmission cooler, and tow/haul).
We usually kept the fresh water tank full when we dry camped, 'cause ya sure can't fill up when you get there. Going to full hook-up sites, we ran about half full, for use in route.
It towed fine, and if we ran at it's "sweet speed" of about 58 mph (2100 RPM), it got about 11 MPG.
Having said that... going up long grades of 6% or greater, it wouldn't go over about 45 MPH. Wish we had the new F150 with a V-10... oh well.
We switched to a Jayco motorhome with the 305HP V-10, and hills are no longer a problem!
Happy and safe camping!
2016 Redhawk 26XD
Me, Dear Wife,
2 Bluetick Hounds
1 Newfoundland / Black Lab Mix
1 Cairn Terrier