As you may or may not know, Stephen, Caitlin, Millie, and Connor are confirmed for the TrackMaster range! Also a few other destinations and sets have been confirmed for King of the Railway too. Source: [1] Let me know your thoughts.
Update: Castle Quest Set will be coming out soon as a set.
Update: As of April 22, 2013, everyone is availiable, except Millie.
Stephen%22TheRocket%22.jpg "TrackMaster(Fisher-Price)Stephen\"TheRocket\".jpg (44 KB)")
Connor%27sRacetotheCastle.jpg "TrackMaster(Fisher-Price)Connor'sRacetotheCastle.jpg (49 KB)")
Caitlin%27sPassengerExpress.jpg "TrackMaster(Fisher-Price)Caitlin'sPassengerExpress.jpg (48 KB)")
CastleQuestSet.jpg "TrackMaster(Fisher-Price)CastleQuestSet.jpg (139 KB)")
TheQuestfortheCrownprototype.jpg "TrackMaster(Fisher-Price)TheQuestfortheCrownprototype.jpg (113 KB)")