Just to echo what others have said, in metric Australia, I frequently get 330kms per tank with a combination of town (at 60kph) to highway (at 110kph) going to work. (110kms/day)
On long trips, my fuel economy improves, with my maximum thus far, being 393kms on a tank.
If you can sit behind a truck, or even car, your economy improves as the wind resistance decreases markedly. (within 30m, you don't have to be right behind)
As proved many, many times - once you hit reserve, and your odometer changes to F:, you are good for a further 60kms.
I have topped the tank off on the side stand, then put it on the centre stand to see the difference and it's a bit over .5L, so 10kms or so.
Plan your trip with 300kms between fills, and you'll be fine.
Cheers,
Rick