Board Thread:Wiki-Related Discussion/@comment-1894786-20150219032755/@comment-34924658-20150220224209

I'd say
 * 1) Season 1
 * 2) Season 2A (Cora)
 * 3) Season 2B (Tamara and Greg)
 * 4) Season 3A (Neverland)
 * 5) Season 3B (Zelena)
 * 6) Season 4A (Frozen/Snow Queen)
 * 7) Season 4B (Rumple and the Queens)

I don't think every single arc would be needed, just the seasonal ones.