Thanks for your help, everyone. I came up with a solution late last night that also works to cure the "awake for 24 hours jet lag" problem. Instead of immediately jumping to the continent like I originally wanted (but the flight schedules from Gatwick were not cooperating), I found a really cheap price on a hotel that is in the airport. So on April 3 I will immediately go from customs to a hotel called "Bloc," catch up on sleep there, then catch an 8:15 am EasyJet to Bordeaux on April 4 -- hopefully bright eyed and bushy tailed. Train from Bordeaux to SJPDP, sleep one more full night, then I'm leaving on my target date of April 5 still. That works, right?
What was really giving me angst is the fact that I KNOW I will not sleep on this 9 hour overnight flight from Seattle. We were in Paris last fall and once again I could not sleep a wink on the flight. My husband secured tickets to a Paris St Germain playoff game our first night, which should have been a thrilling game, but I was a walking zombie having not slept in 36 hours. I was really panicking last night thinking about having to stay awake after that long flight with my pack waiting for a 9 pm flight to France. I could not start my camino in zombie mode! Ugh!
Maybe eventually some day my brain will decide it's ok to sleep on planes. 25 years of intercontinental travel and my brain still mistreats me so.
Thanks again!
