Early dinner at a decent restaurant in town (in Vegas that should not be too hard). Two martinis (no more) before dinner. A bottle of good red wine with your dinner (again, in Vegas this is not too hard). Get a limo booked to take you from the hotel/restaurant to McCarran at about 2000, and be in the lounge for 2030 (maybe push it 15 mins earlier because you might be a bit weebly at this stage). Have a small after dinner brandy in the lounge and then head for the gate. Ignore the boarding Champagne, it'll give you heartburn. Ask the kind cabin crew to bring you your favoured nightcap when they have a moment, then get changed into PJs. Take off, seatbelts off, seat becomes bed, you get your final drink (or two), turn over, sleep. 1400 GMT, wake up, freshen up, have a small breakfast (tea and yogurt), and then feel good about yourself.