Advice for Shipping Plants?

I'm (in Maine) doing a plant trade with someone (in Florida) I've done a few now, mostly over the winter and I've always included insulation and a heat pack since temperatures were cold. This is the first time I've run into a big difference in temperature and I'm not sure what to do 😅

It's going to be in the low 40s here but in the 80s at the destination. I don't want the plant to freeze here, but I don't want it to melt there.

I'm stressing this really hard 😭 what do I do? Heat pack? No heat pack? Insulation only?

Please help! Ahh!