On one level, not having been in the region, how a kid that young could have wandered far enough that searchers couldn't find him."

It isn't that hard. One of my most baffling searches was for a two year old last seen within a quarter mile of his home. The intensive phase of the search lasted for more than a week, involving many resources, coming up with no clues or signs whatever.

Years later, his remains were found at least five miles away (I am a bit hazy on the details) while cleaning out an irrigation ditch. Swiftly flowing water transports very rapidly....