I did a very similar trip a few years back, from NY to Odessa Tx and back. I did it in 4 days round trip. Drove there in a new Carrera S, and drove back in a 1 yr old Carrera. The Carrera S was really a blast, but it really abused my back, especially in Arkansas, whose interstates are horrible. Needless to say, I kept a pretty decent average speed. I was very tired when I got home. My limit for a day's driving is about 1,000 miles. I think the X5 is a great road trip car; very effortless for long trips.

My recommendations are simple: Get a Valentine 1, and a Passport Laser Jamming system. The Passport Laser jammer is a permenant install only. I have both in my DD, and while no system will give you immunity, these really help. Also, watch out for cops with lights flashing on the shoulder. In a number of the states you will be traversing, if you don't move over one lane or drop your speed to 10mph below the posted limit, you will get a very expensive ticket. In some states, like Tennessee, they set traps for this. Also, make as much use of daylight driving as possible if you want to make time. While traffic is lighter at night, you have little chance to see a hiding PO, and it's better to be going fast in a pack of cars than going fast by yourself. When I need to drive this distance, I get on the road at 5 or 6 AM.

Since you want an adventure, if you want to check off a "Bucket List" item, your route will take you parallel to the Blue Ridge Parkway. It is detour that will not take you too far out of your way, and it is an incredible road. But it is also closed for much of the winter, so depending on when you go, you might want to check.

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2014 BMW 328i Xdrive
2011 BMW 335i M-Sport
2008 BMW X5 4.8i Sport
2000 BMW 528i 5sp