I traveled several times while nursing. I overnighted almost 50 ounces of my frozen milk to Telluride, Co from San Diego using dry ice - I had someone unpack it and immediately put it into the freezer. The dry ice worked great - my local postal corner knew how to pack and ship it properly which is really important. Oddly enough it's labeled hazardous material (prolly cuz of dry ice).
Definitely call the hotel, you could ship to them and have them immediately put into the freezer. You need a contact who will promise to do that. Once it starts to thaw - you can't refreeze. If I got low on the frozen milk, I would give 1 bottle per day of formula.
I also pumped while I was on any business trips and packed it in ice and checked it (for short trips)! I couldn't bear to throw away that milk after the effort to get it!!