Currently towing a 2010 Honda CRV (3,400 lbs.) with my 2011 Fleetwood Southwind V10 gasser. Towing capacity for the RV is 5000 lbs. Am considering a 2014 Ford "Edge" that is about 4,400 lbs. Should I ...
Are you concerned with filling a 50 gallon gas tank more up to the 44 gallon mark rather than the 34 gallon mark?
I see no reason to be worried about the extra weight, provided the tongue weight and combined weights are within spec (which I suspect is the case). I doubt there will be any significant change in mileage, though there may be a tiny bit. As enblethen said, slowing down a little will probably do far more for your gas mileage than altering your toad's weight by a thousand pounds.