Count Down

I can hear London calling, and I will be answering that call soon, so very very soon. I can't wait to spend 10 days with Steph seeing England's capital, as well as a quick trip to see Salisbury and Stonehenge. The problem is I don't really know how to count down from now until then. To start I don't know what point to count down to.
-The day we leave, Jan 15th
-The time I leave work to go, 4:00pm Jan 15th *I will use this*
-The time the bus leaves, 5:00pm Jan 15th
-The time we get to the airport, 6:55pm Jan 15th
-The time we are scheduled to take off, 10:25pm Jan 15th
-The day we arrive in London, Jan 16th
-The time we are scheduled to land, 10:00am Jan 16th
-The time we most likely will be in London after landing, baggage claim, customs, and the train into the city, approximately 2:00pm Jan 16th
Then there is the whole issue of how to count down. Using the leaving work date and time there is so many different ways to think about the amount of time left until that point.
-12 days, counting the day we are in
-11 days
-11 days, 5 hours, 31 minutes
-269 hours
-16170 minutes
I still think the easiest thing is to resort back to childhood Decembers and the count downs to Christmas. The age old method of counting 'Sleeps.' It seems to give the best indication of the wait before an event. Similar to days left, but feels easier to picture.
11 MORE SLEEPS UNTIL I LEAVE FOR LONDON!