cyndibelle,
I was just doing this calculation myself earlier for a different reason. We have a trip planned for next February and I was trying to figure out the total cost of the Auto Train. (We are going to take the Auto Train even though it is more expensive because of the adventure of train travel, but I still wanted to do the math as info.)
We are in West Chester, PA - which is about the same distance as maineville, OH from WDW. I also drive a Passat Wagon (2004 with the 1.8T engine).
Total distance for the trip (not including running around Orlando while there) is just about 2000 miles roundtrip.
The math then is pretty easy it is just (total distance / average Miles Per Gallon) * Price Per Gallon of Gas.
If you assume $4.00/gallon for Gas and 25 MPG for the Passat then you get:
(2000 miles/25 MPG) = 80 Gallons of Gas
80 Gallons * $4.00/gallon = $320.00
Both the gas price and MPG above are conservative (you should get better mileage on a highway trip in the Passat, and gas prices should not be $4.00 per gallon on average) so the actual cost of gas is significantly less - probably closer to $250.00.
Note though, that this is just taking into account the out-of-pocket expense of gasoline. There are other expenses in driving each mile in your car. When you factor in the wear and tear, scheduled maintenance, depreciation from additional miles, etc. The price can be much higher. Edmunds.com has a true-cost-to-own rating that they have calculated for each car they rate. For the 2004 Passat Wagon, the cost per mile is listed as $0.49 - that would make the total expense about $1000.00 (this includes the cost of gasoline as well).
I don't know if I agree with the $0.49 being applicable to this type of trip because a lot of things like the purchase price of the car and financing cost (if any) would happen even if you left the car behind and flew. I'd say it is more like $0.35 per mile total for a vacation trip, but that still comes to $700.00
Ted
