Over our first proper French lunch in Chartres earlier - the foodie will be blogging that - I was trying to think of international journeys which had happened whilst I slept.
You know the type; proper going to bed in one country, and waking up in another. There was a memorable train journey across a tiny part of Russia in 2006 but I couldn't think of any traversing of borders like yesterday's overnight ferry crossing.
For the past week or so I've been waking up thinking of this trip. The alarm would go, and my automatic reflex was 'where am I?'. An odd feeling when you're in a static comfy bed, yet clearly I was on the move mentally - crossing some mental thresholds.
Connected with this alertness is a recent development borne out of Clare's Marvellous Medicine. For whatever reason I need less sleep than I used to, which frankly is a relief. I seem to be consistently staying up later, and awake and actually running around much earlier.
Not that it's made a difference to my ridiculous ability to hear a gnat fart three miles away. It's still a trial to stay asleep if there is the slightest ripple in the air around me.
Therefore this trip means pushing my new energy to the limits because, as one night on the road - ok sea - shows, sleep is going to be elusive. Although the sway and rumble of the ferry would probably act as a large cradle to most, I was alert to everything.
I admit I was also excited to simply be on board. Leaping up to peer out of the porthole at 4am to see how big the waves were was both comforting and exhilarating.
However the physical and mental exhaustion of travelling so far - no matter how comfortable the car or how often the coffee breaks - will clearly be a challenge. But this slow over-land and over-sea journey really matters. The distance seeps into your sleep and slowly into your consciousness, making you appreciate how far you've come.
The destination is never as important as the journey; an unoriginal saying, but true, nevertheless.