The majority of people usually arrive on Friday in time to: unload the car, clean up (especially if they drive a Se7en), register, take a look at the cars, get a quick drink and attend the evening reception. Usually the reception has enough finger food to satisfy all but the most famished. The reception never really ends, the food just runs out and people migrate to the hotel's common areas to continue talking, drinking and looking at cars.
The hard core LOGgers and some who want to do some tourist activities will arrive at the hotel sometime Wednesday or Thursday. The trick on these days is look for Lotus logos and say hello. Impromptu groups form for meals and sightseeing.
Maybe: 1/4 leave Sunday evening, 1/3-1/2 Monday, either in the morning or after visiting the Glenn for a bit. The rest fade away Tuesday and beyond. If there is an opportunity to do some touring laps at the Glenn many more people will stay over Monday night and leave Tuesday.
The LOG survival guide
http://www.lotuscarclub.org/logsurvival.php