If you plan on doing this regularly, I wouldn't want you to pound miles onto your vehicle if it's a newer model, so might I suggest checking Enterprise to see if they are doing weekend promotions for car rentals in your area? Sometimes you can snag a small car for $20 a day or less renting weekends in-state. That would save the wear-and-tear on your car and probably, in the long run, add to the value of the promotion by negating depreciation effects on your car. Plus you can choose the best mileage-getting vehicle to save on gas.