A week.... We went from Seville (Spain) all the way to Germany.... But we had a 2 days break in Paris, spent an evening in Salamanca (North Spain), ... and yeah.
In 2008 after graduating I went cross country with my brother. I started by taking a 1way from Maine into San Fransisco. Then driving to LA > Las Vegas > Colorado > Chicago > Ohio > New Jersey > Back to Maine
The longest was when I was probably 6 or 7 and drove to Virginia from Nevada, no idea how long it took us since I barely remember the trip..only certain parts
The longest I have gone that I can remember is last year I drove to LA so that took 13-14 hours