Yea, i get in the 8-10mpg range as well when towing as well with my EB.. I have been happy with how it performed towing by 267bhs, as well as daily driving..
I think there are tons of tow vehicle threads on there, but when looking for your tow vehicle, the thing that I learned (after the fact), is that the most important number, is going to be the payload sticker inside your door. It is very easy to think, "It can pull 9000lbs, so i'll have no problem with this 8000lb trailer...", but really you need to make sure that its payload capacity handles your needs.. My trucks payload is 1368. With a 7000lb trailer, I am using approx 840lbs of that in tongue weight + another 100-120+lbs for the hitch/propane/batteries.. That leaves only around 400lbs for passengers and any other gear.