I've been asked by a national TV station to do a documentary on, well basically on the project that I started a few months ago. Has anyone ever done a photo documentary? If so, how was the experience?
Congratulations. So, my understanding here is that THEY will be filming you, and not you filming for them. They will be watching you shoot and recording it. Interesting topic here too.
If they are recording you, just do what you would normally do. Documentary work relies on truthfulness from the person being documented, so don't change a thing. Be open and cooperative, but don't lose yourself by chimping for the camera. If you have some specific plans, let them know in advance, so they can plan their gear needs in advance. They will most likely want to tape a wireless mic to the inside of your shirt, so wear a button-down shirt if you can. In addition, they will most likely have a sound-person recording with a boom mic as well, just ignore them unless they whack you in the head with the mic.

Otherwise, enjoy the experience and don't set up shots... be ethical in your dealings with these people and simply do what you would normally do. If they ask you to pose, simply tell them "That isn't something I would normally do" and explain to the producer what you WOULD do. If they are ethical, they will appreciate your honesty.
Best wishes for success.
Cordially,
Mark
Thank you Mark. That's the kind of insight I'm looking for.
Best,
AC
(BTW, I teach documentary film making...)