If travelling by car, put your cake in the footwell of the passenger seat if it fits, or in the boot if not. DO NOT travel with the cake on the back seat or on someone’s lap. Keep your car cool, ideally with aircon on if it’s a hot day.
I recommend that you collect your cake on the day of your event if possible and store it in the fridge. Bring it out to get up to room temperature before eating, this will take 1-3 hours depending on the season. Cakes will stay fresh for up to 3 days in the fridge. Cupcakes should be stored at room temperature and will last for up to 3 days.