This all has me concerned. Where did you find this person? Do you know this person? Why are they shipping if they have never shipped/don't breed? Have you paid for the shipping already? If they are giving it away for free why couldn't they find someone locally? I'm concerned they are looking for a quick $50-$60 and they aren't going to send the snake. Hopefully I'm wrong, but I'm worried.
As for shipping.... Snakes should not be shipped late in the week, I won't ship past Wednesday. If the box gets lost, there's a chance it will be lost for days (over the weekend) which is really bad. Shipping in cold weather is fine if the shipper knows what they are doing. Heat pack/s on the bottom, lots of insulation, and a small box are the main things. I only ship hub to hub (airport to airport), especially in extreme temps.