3100 mpg 4x4

ok - i have some info this is not complete and bean counter nit picker types need not continue as these numbers are possibly capricious and arbitrary, also not yet complete.  As I am beginning to rebuild the spreadsheet, I picked 20 sets out of my day planner/scraps of calendars,etc.  At this point, I did not factor which grades of gas gave what mpg. Nor what I was pulling at the time-I have the info, just haven't rebuilt a relational data base from which to easily yank the info.
 
After about 11,140.3 miles on PC & 40ish hours on generator, mpg goes betwixt 5.6 to 9.8 with most appearing 8.1 to 8.8.  I do not know how much gas was in PC when we picked her up she had about 70 miles on her & i bought gas 30/40 miles later - no, i'm not sure where the receiptie thingy is & I'm not prepared to admit 'tis lost. So, my info starts around 370.9 miles.

We have hung 900ish pounds of Piaggio off the transom (Stuart asked with straight face if I thought it would make it to Florida)(and back), pulled 1000 lbs of Piaggio & trailer around the NE (that was special around Boston), towed the tri-toon to Apostle Islands (I think Aimee put that pic on the web page).

The ride while towing the tri-toon was still very comfortable, acceleration tended to be a bit sluggish  actually better than I thought it would be. 
Happy Travels
kevin

I think of this at random times and that is to log the hours of the generator at each gas fill so how its usage affects mpg can be noted.

If you mean by "grades" of gas regular, intermediate, and premium, there should be no repeatable differences between grades.  While the composition obviously varies between grades, the only reason for using premium over regular is to prevent knocking.  Premium is not necessarily better in any way than regular except for octane, although some manufacturers use more detergent additives in premium. All name brand gasoline has sufficient additive packages in regular grades.  Also, in many cases the additive packages are the only difference in gasoline brands.  Bulk gasoline made to federal specs goes to terminals and the additive package is put in at the time the trucks are loaded to go  out to the stations according to the brand of the stations being filled.  In other words, don't worry about grades and mileage unless you're marginal on octane.  If so, many vehicles are set up to prevent damage from knock by automatically retarding the spark.  If this is happening, you will be getting less mileage.

Jerry