Her car was found, her phone was found (like a needle in a haystack, finding that) footage was found showing when she entered Dale's complex and it very likely shows him or her car or both, leaving as well. That's much more than a trace.
They are searching a fairly tight area. They have their sights on Dale. The map shows a straight trajectory down one highway, from his house, to where her phone was found and then her car, with his dad's house, the very place he claimed to have gone after she dropped off the kids, in the middle.
I think it's clear that LE have a lot to go on. Even without knowing what they have that they refuse to release, to me, what we do know looks like a giant target pointing right at Dale and his father, simply looking at a map.
Nah, LE is not running aimlessly in circles. They know where they are going, what they are doing and why. And Dale is not smarter than most common criminals, IMO.