Let's get back to the sad basics.
Gannon is missing.
Assuming that's him getting in the red truck, he was last seen at about 10:15 that morning.
That's like our starting AND ending point because our source of most information is TS.
TS had full control (possession) of the house until LE showed up around 10 pm. When did AS arrive home?
We don't know if there are additional comings and goings from the house. We only know, per LE, there were no more sightings of Gannon....
We are left, by my calculations, with very narrow windows for -- no way to say this delicately -- disappearing an 11 year old. Vast landscape for sure but honestly where would a person go, how would they feel assured they'd gone far enough?
Ravine? Dumpster? Waterway?
He has to be somewhere.
JMO