Ditto. In fact do a YT and or Google image search for the now in-famous shots from videos of Mr Olympias Jay Cutler and his 'bro' Phil Heath with what looks like GH or (at the very least) peptides in their fridge doors. You don't want to freeze them any more than you want them overheated. So a cool box with a cold pack but not right next to them. Depending on how far across country you're going and how long it takes you might wanna add a new cool pack as required.
If they're already mixed then keep them refridgerated....if their still in powder form then try to keep them at room temp away from excessive heat. Fridge or ice pack is still the best option for either scenario.