Towed my 19' Shamrock weighing in at about 4500lbs plus 2 adults and gear in the cab and bed. 8-9 mpg. I thought it towed pretty well though lacked power up steep hills. We never went further than about 3.5 hours.
Traded it in for a Ram 1500 Ecodiesel, As an every day car the Ram is way more comfortable than the Ridgeline and mileage while towing my 7000lb camper is 14-16mpg

I loved the features of my Honda, had thay come out with a V8 version and more towing I might have gone that way but I'm completely happy with my Ram 1500 Ecodiesel