I'm not sure what you mean at the first part, do you mean like you need an item for a teleport? If you want that than you can have the event like this:
The teleport you set a fork conditions, and make the condition a switch turned on, lets say, hooki, and that is turned on when the event you want to happen happens, just add a change switch to that event and name it hooki. Then you click ok on the fork set to hooki on, then you add a teleport inside the fork to the new location, that simple. For the chest make it like normal and have the item gained and sorts, at the end of those events turn on a switch such as, chest opened, now add another page to that event, with a picture or an open chest. Make that page activated when the switch, chest opened is turned on, now they can't get it twice