I also remember coming back from the Bol D'Or (at Paul Ricard) in the 80's, the year the race was rained off in the middle of the night. Our tent got swamped under 3ft of water, so we slept outside the toilet block, with about 100 others, after getting royally p*ssed. The journey home started with me with a massive hang-over, but tearing up the Autoroute at 140mph all the way. The Police were sat at the side of the road waving us on and giving us the thumbs up - and with the nearside toll booth at each Peage being open for bikes (no barrier), we were going through there at a fair rate of knots! - I seem to remember filling up about every 110 miles too on that journey.
Its a pity those days are long gone....I remember the Autoroute Peage's being closed from about 12.30pm to 1.00pm on the Friday before they opened the booths for bikes (to let the routes "empty" of bikesbefore the made them free) and we didn't get issued toll-tickets, because for that weekend, all the Autoroutes down to and back from the Bol were free for the weekend.