I use unblock-us to access services that have this really stupid idea of IP-based positioning (hey guys, my IP does not mean anything!). This service (like many others) proxies your DNS traffic through their own servers so you can pretend to be anywhere on the planet. You only have to add their DNS-servers to your computers network settings or to your WIFI-router so all your devices can use it without changing their configuration.
Unfortunately, the chromecast has it's own google DNS configured and those google assholes don't let you change it or disable the feature. In the linked support thread, you can see how you can spoof the DNS traffic using
iptables in your router, so the chromecast will actually talk to unblock-us instead.
My WIFI router is an oldish Apple Timecapsule and those things are quite when it comes to co