Beyond the Season of Ghosts
Season of Ghosts ends at Level 13. Below are the available options (as far as printed APs go) for continuing after Ghosts ends. Most of these start at level 11 or 12, so some tweaking of their starts will be necessary, but shouldn't be too problematic/difficult.
Fists of the Ruby Phoenix
Resonates thematically with the Asian themes of Season of Ghosts
Curtain Call
Provides callbacks to your accomplishments/encounters in Season of Ghosts, but more RP heavy and a thematic shift
Spore War
I think Night may be planning on running this one already.
Revenge of the Runelords
Mythic adventure, but likely callbacks to earlier Runelords related APs. Unsure of how much prior knowledge/exerience would be useful.