Hey I have used a snugglesafe pad when the travelling it is good for 8 hours or a bit longer really you need to wrap it in a blanket or towel but they are really great products.

http://www.snugglesafe.ca/


In case you have never encountered one. I got mine for a vet if there is the a storm warning I'll pop it in the mircowave and then in a cooler bag just in case the power goes out.

Good luck and have a great vacation!