As most other promotions ask you to just reach Level 5, or Level 6 in the case of FarmVille's promotion, if you've already done that, you should have little to worry about. If this is your first time playing the game, however, you can easily reach Level 5 in one or two sittings, shortly after finishing the in-game tutorial.
Regardless of when or how you make it to Level 5, when you come back to Adventure World, you'll receive two bonuses for completing this cross-promotion: a free Victorian Statue for your Base Camp and a complete Energy Bar refill. As energy is the biggest commodity in Adventure World, that's a pretty great prize (especially if you're down to the wire on completing one of the game's many Expeditions).
It's likely that this promotion will only be available to complete for the next few weeks, so make sure to play Hidden Chronicles quickly. After all, you'll receive rewards in almost every Zynga game on Facebook, so why not claim as many as you can?
Have you already reached Level 5/6 in Hidden Chronicles, or will you just start playing the game now for these Adventure World rewards? Sound off in the comments.