Most people can connect their Chromecast to their hotel TV and use their phone to have it use the hotel wifi. This runs into the following hurdles:

  1. Some hotels apply limits on no. of MAC addresses that can connect per room
  2. Your Chromecast becomes visible to other users on your hotel's wifi
  3. Your Chromecast needs to be re-configured using your phone when you move to another hotel or move back home

In place of the simplistic setup above, I prefer setting up my own fixed, firewalled wifi network that extends the hotel wifi. One of the lesser known features of a 4G Hotspot device is its ability to work as a Wifi extender.

I use an unlocked Huawei E5573s-606 4G hotspot device to create a private wifi network extending the hotel wifi.

Chromecast is configured to always work with this 4G hotspot. Even at home! Only thing that changes is the wifi network configuration of the wifi network being extended.

If, for whatever reason, the hotel wifi stops working (power cut, etc.), switching the device to use 4G makes everything else work seamlessly.