Traveling from seattle wa to knoxville tn, needing help with math lol?

At 2,579 miles, it would take approximately 81 gallons of gas if your car gets 31mpg. 81 X $4.00 a gallon for gas is right at $333.00. Including having to stay over night several nights, buy food, drinks, etc. along the way, I would say it would be a lot cheaper to fly if you don't need your car when you arrive in Knoxville. If you have a newborn, most airlines allow you to hold your baby while you fly at no charge if you are flying within the US. I would check with the airline that you choose though to make sure that they do not charge a fee now for children under 2. Good luck!