I have zero experience, but…
I guess if you phoned a local bike shop and asked if they could keep you a box during the post-Christmas lull in 10 months time you’d be out of luck. They might have a box, but remembering and then keeping them hanging about the store especially for you sounds like a lot of hassle.
If you show up at the end of your ride, ideally with a weekday in a hotel, you’d probably be able to ask nicely in a bike shop - or just buy some big bits of cardboard/ padding / fancy bike box on the day.
Also, what are you using for the way out?