We have travelled from northern Vt. to Cocoa Beach a few times in many different vehicles, Ford Escort, Tauras, and Expedition. Each trip (1450 mi. one way), we had our camping gear, 2 adults and 3 kids and those vehicles cost us 350 one way. I now have a 2001 Silverado with the 4.8 v8, 29 gall. tank, and the last time we went down 2011, it cost us the same amount, 350.00 one way. I know it sounds strange that four different cars would have the same cost, but I always keep track, I know where I have to make it to before I get fuel. Then once we get to our destination, well we go through about 200.00 just driving around for 2-3 weeks. Not only does it depend on what type of vehicle you have, but also your driving habits. I don't have cruise in my truck and I do find myself driving below or a little (10-15mph)over the speed limit. Not sure if this helps or not, either way have a safe trip.