If you're traveling by car, just get an electric skillet.

http://www.walmart.com/ip/Oster-12-D...Black/27436248

Otherwise, most hotels will have a microwave you can use, either in the office or the breakfast area, if they don't have one in the room. I've got one of these soup mugs that works well for heating things up and packs in a suitcase.

http://www1.macys.com/shop/product/c...744|-|4pyNsMQw