For the Festival of Fears portion of the event, be sure to talk to Reginald. Once you see all he has to say, you'll be able to find all currently findable Goodie Bags! You may interact with any of the Activities and the Fright Track at any time while the Festival of Fears is active, though, without having to talk to Reginald.
As for the Kanrik Chronicle Event, this can be started at any time by making your first choice. Learn more about it at the Kanrik Chronicle FAQ.