My longest trips have been to Iowa and back to Georgia, which my wife and I do 2 to 3 times a year. 850 miles one way. 1700 miles round trip. We have a 7 year-old, 2 year-old and a dog with us whenever we go. It normally takes 14 to 15 hours driving straight through at a steady 80mph with several 100mph stretches. The first time I went, I made it in 10 hours by myself. Heehee.
Of the states I normally go through (GA, AL, TN, KY, IL, MO, IA), I try to avoid Illinois the most. [:'(] It has the worst roads and worst drivers.