Yes, there are areas where stations are a good distance apart. The flipside of that coin, and every coin has one, is that riding style can have a significant impact. Realizing any numbers given are subject to conditions, the BMW F800 is listed at 55mpg at 75mph but jumps to 69mpg at 55mph. With a 4.0 gallon tank that's 220 miles or 276 miles range. I don't think our bikes can match those numbers but we have an extra gallon.
Yeah, I know all the arguments and all those have a flipside too. At 55 you have more time to react. Stopping distance is much much shorter. Scenery is much less of a blur. You can get away with looking around and enjoying the ride with far less risk. Your equipment is much less stressed. And I'm sure a number of others that offset more of the arguments against slowing down.
There actually isn't any written rule or factual evidence that motorcycles can only be enjoyed at high speed although it's a prevalent urban myth and not untrue in it's own right.