For every minute you film you can count on 10 minutes of editing. I have no scientific proof of this but it's what my gut tells me.
Slow, painful, boring editing. Fair enough if you're getting paid to edit something, but for the rest of us the idea of spending hours in front of the computer after a ride is enough to just leave the camera at home.
The art of a good travel film that doesn't take an eternity to edit or abandoned in a fit of 'f**k this shit' is literally to film as little as possible.
And the art of filming as little as possible is having a good idea of what your story is.