You can usually find both films on YouTube. I wouldn't exactly call either film fun or entertaining.That’s an interesting call-out because I’ve had The Rain People on my list forever and was recently thinking about it after Megalopolis, but hadn’t heard of Filmmaker. I’ll see if I can track them down.
The Rain People is a sort of allegory for what American Zoetrope can do as a lean, anti-bureaucratic organization operating according to a different type of ethos.
Filmmaker is an addendum to that argument, but also Lucas's own contribution to the question of why directors, and not studio producers, should have control of the making of a film.