We ended up buying a Fridgidare unit at walmart. Its located on a counter top and makes enough cubes for a cocktail glass in about 6 minutes, and even quicker if you prime it with a couple of cubes from the freezer, when you first turn it on. We have a small adjustable strap to secure during travel
Just make sure you allow for good air circulation around the unit to improve cooling.
Safe travels and all the best