It is really all about the packing, I have received trees that took a week in the Summer and they were fine, I have received trees shipped from Dallas and Houston (2 days) that were a wreck. Two days is kind of optimistic, figure worst case. I received a tree from Michigan that was wrapped very well and would have survived a couple of days in Summer or Winter.
I don't care what you do, or when you do it, or how well you do it, there will always be a bad one, lost/delayed by the Post Office, delayed due delivery to wrong address, or something else that is unforeseen. Do your homework, do your best.