Short answer: Get an
Amazon Fire TV
Long answer: GCH (and most hotels) utilizes a captive portal which requires accepting terms on a web page. Apple TV lacks a web browser, so there is no way view the web page to accept. When hardwired ethernet was available (prior to the renovation) I used an Apple Airport to create my own wifi network for an Apple TV. It might be possible to contact the hotel IT department to authorize an Apple TV (by the ethernet address), or spoof the ethernet address on another device -- either option is too much like work for my vacation.
I tried the Roku Stick (at GCH) which uses another device (your phone or tablet) to view the captive portal page, but this was not reliable. While the Roku worked for several nights, it required several restarts and eventually stopped working.
The Amazon Fire TV 4K (lower priced Fire TV Stick should also work) worked without issue in both a VGC room and a pool cabana during a visit this past June. Fire connects to a HDMI port on the back of the TV and power can be supplied by a USB port on the TV (or a power adapter). Try Fire TV at home, to load required apps and authorize streaming services. iTunes is not supported, but purchased iTunes movies (not TV shows) can be viewed on using Movies Anywhere (aptly named).
Important Note: Depending on the specific TV model (or configuration) it can be confusing to select the HDMI input. The INPUT button on the TV remote will work on some TVs. On other TVs, scroll through the channels to find the HDMI input (channel 92 or close). One of these methods should work on any tv at GCH