If its a candidate in your mind then you dont have much time but probably enough time to arrange a few phone calls. I would do some prep work and then get in contact. Weekend or not if they really want you then at the very least the DGS will give you an hour to try and convince you to attend. If not then dont think too hard about it and pick from your existing offers.
Well done on making your decision. I think its brave as I dont know anybody who would turn down both Princeton and Stanford for anywhere other than Harvard. I think it shows you thought long and hard about it, which is to be admired.
I am wondering if it would be a mistake to ask faculty about their future plans? I know that when it comes to faculty moving university its not straight forward but what about retirement? Five years is a long time so would it be a valid question and how could you bring it up gently?
Its a bloodbath of OSU rejections today......keep the chins up. If it make anybody feel better no doubt when the Princeton results come out it will worse