From the "Find Cole" facebook page, they have also created a search map, asking volunteers to identify areas they have searched (but only if they have thoroughly searched)...
http://codergrl.maps.arcgis.com/apps/Editor/index.html?appid=fddd538b8d0f4d04af304a7d11e33c84
I thought this was a really good idea. I can see that not much has been explored in Battle Ground. I need to do some work in the office this weekend, so I think I'll drive my usual route out there, then drive a different route home and do some scouting.
There was a local rumor that Cole's phone pinged in north Clark County after he went missing. I can't find any confirmation of this-- but I saw on the Clark update that they stated his phone pinged "north of the college". That may be where that came from. (If you look at Clark on a map, the college is very close to the Oregon border, so there's plenty of Clark county that is "north of the college", but would not be considered "north county" by any stretch.)