I took this first photo in July of 2014. Since the work was being done right over the fence and only a couple of hundred feet away from the KT Corral camping area, I was sure they wouldn't be building a house there! So I kept coming back to check progress.
By September, it was definitely looking like a housing pad.
You can see the shipping containers on the left that are used by the rangers for storage at the park. December 2014.
And then not much happened until the Spring of 2016.