Mosquito Coast! This is a terrific movie from the 80's starring Harrison Ford, Helen Mirren and River Pheonix that I need to watch again.
Ford plays a married man who charismatically lectures on the hypocrisy and corruption of America to anyone who will listen. Especially his family. So He decides to take his family back to nature and live off the land in the rural rainforest of South America. Trouble arises when he buts heads with missionaries and bandits.
The movie is kind of told through the eyes of the son played by Pheonix as he sees his father become unglued and his family threatened.