I have found this amazing production blog about a documentary on long bike journeys.
I suggest you to explore their website: http://projectpedal.com/
You will find a very good guide about how to make a documentary and great video materials.
Inspiring.
One of the best quotes: "Because in the end it has almost nothing to do with the bike and everything to do with setting out to accomplish something that is intimidating, that is unknown to you, something you know you have a good chance of failing at but doing it anyways and slowly but surely proving yourself wrong."
