We took I20 from Texas to Alabama a couple of years ago. I have never been on such bad roads. Many places I couldn't go more than 35 mph or my suspension would bottom. I agree that you'll find weather across Tennessee and Virginia on 40/81, but I've driven it in the snow and the road stays pretty clear. Lots of trucks. I'd go 10 to San Antonio, 35 to Dallas, 30 to Little Rock, 40 to 81, 66 to Washington, 95 (or 50/301) to NJ. Worst parts of the drive: Knoxville and the Washngton Beltway.