LE stated early on during the searches that the last digital ping was near the pig farm. CR could've gone past the pig farm on his way to the cornfield, but it would have been going an mile extra south (470th), just to have to turn around and go back north before turning east on 460th. *Please somebody inform me if I have any locations wrong!
I have heard, but have no source, that fields close to where she was found had been searched. Had some digital signals happened around there, too? That I don't know.
Anyway, the location he left her was very close to an intersection (maybe the one he claims to have taken a u-turn) which takes a short jaunt south to 470th. If CR didn't want to backtrack on 460th for any reason, that would be a logical quick route out. The pig farm would be on his way home. If he still had her phone at that point, maybe that's where he turned it off or tossed it, thus the last ping.
Blue line is his route from near abduction site, and green line is his route home. MOO