Yeah I hear ya...
FWIW - my truck is getting 16mpg city and about 18.5 on the highway (empty). I'm sure pulling Frankie would lower those stats a few points; but not that much, the truck does really well with a load.
I'm spending approx. $420/month +/- on gas, so I guess I was pretty close to the 375 miles mark... Looks like it may be just a smidgen different:
17mpg
24 gallon tank
$3.60/gallon (average cost)
$86.40 to "fill up" - never actually costs me that much; usually about $78 ish...
Filling up once every week, topping off usually around Thursday...