The longest sleep I have ever had was after the 1990 Le Mans, where I drove down during the Friday, via Paris and got to Le Mans around 2am on the Saturday of the race. I then got around 3 hours down time, though not sleep to be woken by a French Police officer with a big **** dog telling me the ticket office had opened. I then managed maybe 2 hours sleep during Saturday, watched the entire race and drove home, getting into my pit around 4am on the Monday morning. I WOKE at 11am on the Tuesday! In those days I was fit as a fiddle and I was 100% destroyed for the last 2 hours of the drive home, stopping for black coffee at each service station from Dover to Staffordshire!
Plan ahead, fit in sleeps time and if you can get a hotel in town!