We have a 2014 Citation 24SA. In our recent trip from Vancouver to Ottawa we filled up each day as we went,it usually was combined with a doggy walk/on board coffee break. Price per fill averaged $55-best about $25,highest $70.
In 28 days we spent about $1600 and traveled 11000 km. About 20 mpg canadian I think.I bought the Sprinter based unit because we like to travel and sightsee with our dog and two cats. We kept expenses low by eating all meals on board but we camped mostly no hookups at provincial campgrounds or small town municipal campgrounds which were quite nice,actually. We drove at 95-100 kph which is roughly 60 mph. Everybody passed us but few complained too much. It meant we rarely were following anybody and we got to enjoy the view.
The Thor Citation is well thought out and we find it does everything just right.
I hope this is helpful to you. We had a great time.