SEA has a red carpet club, it's fairly small and I don't think there are any sofas - it seems to be all single seats. It's being renovated and different parts are being closed at different times. If you are REALLY TIRED you could probably get an hour or two of sleep there.
As for the Gray Line - that's interesting, it seems like they guarantee you a ticket. I guess they must have a charter tour deal with Boeing. If you rent a car and do it yourself, you should have no trouble getting a ticket for that day if you get there by 9 or 10. Keep in mind it's a 30-40 minute drive from downtown with no traffic, and it puts you the opposite direction from the airport (about 90 minutes from the airport) Here is the Boeing tour official web site:
http://www.boeing.com/companyoffices/aboutus/tours/
Also call their number the day of the tour and make sure that they are operating that day. Sometimes they close down for a VIP tour for the day.
[This message has been edited by usoftie (edited 09-10-2000).]