On first reading, Day 3 seems to depend on splitting the group and keeping secrets from each group about the movements of Blaine.
I like to play an open game, so I plan on playing one group, and letting the other group be an audience for the story, and then swapping over.
So for Day 3, I intend to play in this order:
1) The surveyor group up until they decide to get back in the truck. Everyone knows Blaine has gone off... but not where.
2) Then back to the folklore group, run back in time, let them interview, and the rain drive them back to the farmhouse. Blaine comes in, makes his excuses... before he can be properly interrogated the Sheriff knocks on the door... Saying that the surveyor truck has been in an accident, landed in the water please come and help. Upon agreeing, switch back to the surveyor group.
3) With a knowing smile, you can tell the surveyor group they're now driving 'safely' back towards the farmhouse... Crash, jumping, swimming, and the two groups can be re-united.
So, the mystery is kept, and everyone gets to hear the whole story without having to make anyone leave the room... or at least that's my plan.
Cheers,
Pete S.