Ok, it all became very real today.  We dropped off the bike and gear.  The magnitude is starting to settle in.  We're going to ride.  Bicycles.  Across the entire continent.  Almost 3,900 miles.
I can't do that.  It's too much, too far, too long.
But I think this gives me a different perspective:  39 miles.
I can do 39 miles.  That's not bad at all.  That's a normal ride.
39 miles is 1% of our ride.  Every time we do another 39 miles, we're 1% of the way closer.
3,900 miles?  That's too big.
39 miles?  I can do that.
So, I don't have to do it all;  I just have to do it 1% at a time.
Sounds like a good life metaphor.