I personally use a Rubbermaid tote. I buy a shit ton of the cheapest paper towel rolls. Line them all up on the bottom to create a good cushion. Put motor in. Then fill in the gaps with more towel rolls and whatever else. Put lid on. Drill holes through the lid on the outer rim where the two meet and put zip ties through to hold the lid down. I’ll also tape it a lot going around and around continuously to secure the lid if the zip ties fail. Been shipping out motors that way for years now with no issues. I also keep the plugs in the motor just barely hand tight. To protect the head ect from any force. Good luck. The cooler idea seems good too. Either way package with care and don’t skimp on it.