I have a 97 Volvo 960 that I use for my long trips. I did some undercarriage aero work that helped out by about two mpg. It has a 21.3 gallon tank so range isn't a problem to Fl. Just to make sure and save the most I throw in four Eagle five gallon safety cans. I top off the spares in South Carolina and when I hit Naples I pretty much have a full tank of cheap gas for the week. On the way home I'll only fill two since I only use the car on the highway and no need to have a full tank sitting for six months or so over the winter.
I would love to see straight gas again she would easily pull 29.50-29.75 on the highway at 65 mph. With this garbage E10 I'm lucky to see 27 mpg on the same trip and speed limited to 65 mph max.
Toss in AC and the running the 70 mph speed limit more like 25 mpg. Keep telling me ethanol only affects gas mileage by 3%
The old Volvo Turbo wagon