March 2016 I bought my 2006 Discovery 39S with 26500 miles on the clock.
We do not have a tow and our top speed is 60-65 mph.
So far I made 5 trips with a total of 19.265 miles and burned 2395 gallons of diesel.
That is 8.05 mpg

I find it's best not to know, when we can we fill up and just take it easy keep to under 2000RPM.

Bazzer

Fleetwood Bounder 7.2liter.

Have a 43’ 2014 Itasca towing a 27’ trailer weighing about 11000 lbs and get about 6 MPG at 65 MPH

Diesel pusher MPG
 

2016 Newmar Ventana LE, 40 ft, 360 hp Cummins, 8.5 - 9 mpg

Cat 325, 37 ft 9 .1 mpg towing trailer, 9.3 towing truck. 150,000 miles.
 

9.3 towing. 37 ft Cat 325 , 2003 Safari 150,000 mi

MOG on 360 Cummins
 

Our in the city and on the road combination MPG is 7.7-8.0 MPG. Not sure what they are apart since my monitor does not calculate separately. Some say they get 8-10 MPG on the road. Still recommend a diesel pusher, quieter, plenty of power and more room to sit up front where you are driving imo

2015 grand tour , 450 isl cumins,towing 4dr jeep wrangler gets 5.5 to 8 mpg depending on terrain wind and speed

2014 Forest River Legacy 300 HP towing CRV. I don’t run wide open on most trips. Usually 61 or 2. I have gotten almost 12 and as low as 7. I think I get better than most bigger campers. It is what it is. If you stress out about the MPG, maybe it’s not for you.

2000 40’ Allegro bus Cummins ISC 8 to 8.5 consistently towing 4 door jeep wrangler

10.1 consistent mpg. 36' 1999 Fleetwood Bounder model 36s with Cummins 6 cylinder turbo diesel cruising at 60-65 mph. It's a year before your request range but thought you'd want to know.

2002 Monaco Windsor 40', 350 towing Ford Explorer Sport Track ... Average between 7 and 8, as a rule. We are in Oregon and have mountains on all sides.

Have not checked milage now that we tow a 2012 Lincoln MKX.

Driving a 2008 38.5 ft getting around 9 MPG when not towing the Jeep Wrangler. Towing I get around 7 MPG.

2001 monaco dynasty drywrought by driverside window
 

I have a monco dynasty with a 350 cumm we travel from fl to mn I pull a buick enclave and and adv. 9- 10 mpg speed 65mph

Almost consistently 5.5. 2007 Beaver Marquis. Cat 13, 45,000 lb.