One aspect that hasn’t been mentioned yet is that The Master himself serves some deity called Manos. It’s possible that Manos is responsible for the moving house/car breaking down/“Valley Lodge” signage. (Of course Manos knows fast local sign makers, it is all part of its dark power!)
Manos’ involvement would explain why things happen The Master wasn’t prepared for or didn’t intend. Manos has its own unknowable plans and ideas.
Isn’t Manos really something that was inside us all along?
I thought Manos was the friends we made along the way.
Maybe Manos is not something you can really quantify. Maybe Manos is found in the laughter of children and the curve of a rainbow.
In the sequel, I believe Jackey plays the actual Manos.
And the child? That wasn’t a part of the plan. Hence The Master’s outrage.
There should be a sequel all about Manos’ nephew helping out the family business:
Sidney Manos: Travel Agent of Fate
Jake from Allstate: Good Hands of Fate
Heh! To paraphrase a Zombie Nightmare riff, that seems a trivial use of Manos’s dark powers.
Manos is sassy, is brassy, it’s a musical humdinger!
What if Manos…is the sampo?
Dun dun DUUUUUUUUUUN!
[keeps the Failure Song on standby in case Torgo messes THIS up]
The main takeaway is this is all Mike’s fault.
Torgo told him to leave, his wife told him they should go, and yet he still insisted that Torgo let them stay.
Signs that said “VALLEY LOOGIE” were never trusted again.
But this was a Joel episode!! 
I could explain the plot of this movie, but Manos would not APPROVE.
Well, we’re here now, and I’m sure Manos would approve.
[ridiculously silly voice]
Well? How 'bout it, @Yolg?
“I don’t kn-know. I just don’t kn-now.”
(Because of this movie, every meeting I’m in, I find myself thinking of the scene where the Master is listening to the wives talk about whether or not Manos would approve, who gets sacrificed, et al. And I go to a LOT of meetings. Though none of them involve human sacrifice. Yet.)
“Are… are you humming the closing theme from Manos during this meeting?”
“The theme, yes. The lyrics, no. Cheese, maybe.”
Well, we’d probably like to forget the theme from Manos, but when I think of that song, I can only think. . .“Forgetting you/is a thing that I cannot do. . .”