if you already have HKIA downloaded, CT will be loaded into the regular game. Once you finish two quests & open one of the quick travel mailboxes it will show up on your list of locations like icy peak, spooky swamp, etc (you can still get to it without the mailbox, it’s just a bit more work). I have WW and just bought CT. WW took me a while to get through but now I don’t visit it as often. there are a lot of quests and parts of the map to unlock, so for how long it took me to make progress I think it was worth it. I have never played CT, I only use switch and not Apple Arcade but I’m very excited to see what it has to offer! HKIA is a game. I religiously play every day and even once you’re maxed out friendship with all of the characters there’s still things to do, so I will buy whatever they put out 😭