John,
When I am going to transport chips in VERY HOT weather this is what I do:
I take two empty half quart liquid containers. Ones that when you seal them they DO NOT leak. I fill them about 1/2 full with water so when they expand they do not split the containers. Freeze them and place them in the corners of a large ice chest. I place my binders, tubes, boxes, etc. in the ice chest and that's that.
Of course this will not work for dealers who move massive amounts of chips. Just us collectors who wish to pick up chips along the way and maybe have a few binders with backups in boxes for trade. It really works well - I even have room for a few water bottles. Best, Jim