On the D&D Birthday Party Organization

I have received so much good advice from my last request, and I just want say: Thank You. Unfortunately, the "second DM" is not an option, because the only player with previous D&D experience is so excited about playing. By the way, I think that Alexey, Telecanter and Zak in particular hit the mark, so this is what I'm probably going to do:

• No pre-gen characters: when you join the party, you sit down for 10 minutes and roll up one or two characters (depending on how long you are willing to play). I will give standard equipment (armor/shield, weapon, class gear) and 1d6x10 gp. I would like to have the characters be able to return to the local shop any time they need some special equipment (i.e. ropes, poles, tent, bedroll, etc.) No need for special fantasy names: if you name your character Gianfranco, I'm fine.
• Marathon gaming: I'm going to allow 6 to 8 characters at a time, you can play until you lose your character(s) or someone else is willing to join the table. If you join the table during exploration, then you use the character of the player who is leaving the table (or a henchman, if his character is dead), and if you join the table during a break at the local safe-place (city or whatever), then you can use your own character.
• Have them wake up in a dungeon: That's a good point from Zak. Instead, I will have them wake up on The Isle of Dread right after a storm. I will locate a small keep for supplies and such, and add some encounters and a dungeon in the close surroundings.
• Girls: Err, don't know. If you are a girl, then I'll be scared to death or something. I'm fine with girls playing Call of Cthulhu (had an all girls party some years ago, we played Curse of Cthulhu and it was amazing, best party ever), but DnD, ugh. Maybe I can add some Pink Unicorns of Doom here and there...