I just had a 180 mile ride to Pymatuning Lake. 160mi's of which were on a full tank that took just over 2.6 gal to fill back up.
That makes around 60mpg
No 2-up, just me at 170lbs.
Average speed was around 60mph at +/-4200rpm's, with not too many twisties
or mentionable elevation changes. Mostly two lane with some of that going through Amish country (bet them buggies would move pretty good with a Vulcan engine in them !! LOL)
I could've easily beat my longest run of 170mi's before filling back up.