Hi E.! Tennessee is a long trip for you all. I've traveled with my son to New Mexico, it's a 12 hour trip for us, and sometimes he's fine, other times, he's really fussy. I've taken him when he was 2 mos old, 1 year old, and just recently we had to go back ( he's 2 years old now). Take "SOFT" toys for your baby to play with(the hard ones will damage the car if she's got a good arm, and or hurt you if she throws it at ya. You don't want that while you're driving), and expect to make several stops. I would stop every 2-4 hours so that your baby can get some exercise to stretch the legs, diaper change, feeding time etc. Take lots of snacks so that your baby can have it on hand when she needs it. Take extra juice (Gerber Graduates Toddler Juice is best since it doesn't have a lot of sugar in it), and take lots of water. Check your carseat and make sure it's secure, and take your car in and have it inspected to make sure its safe too, like the oil change, air in the tires, transmission fluid etc. That way you girls will be safe on the road. The route I believe you should take is the I-40. I believe that's a straight shot. Do not take any side roads. Stay on a well known HWY or interstate like the 40. It's safer that way. Take a road map with you and keep it with you at all times. Mark your path that you are taking so that you can refer back to it when you need to. OK, I just looked at my road map, and the 40 will take you from here (you'll get to the 40 in FlagStaff), and it will take you through New Mexico, Oklahoma, and then Tennessee. So as far as I can see, and with me loving to travel all the time, I would take the 40 all the way to Tennessee. Best wishes to you all, and I pray for your safe trip. Don't speed. :-) Be patient, and anticipate. Those three will help provide a safe trip for you all. Hope to see you back here on MamaSource! Take care, God Bless you and be with you on your trip. G.