Episode 3: Battle of Winterfell - looks like maybe NOT including the Night King. #DoDamage but ultimately the Undead rise from the Crypts
and force our heroes out of the Stark home. Retreat to Dragonstone or Iron Islands.
Episode 4: Regroup, recover, conceive a new plan. Maybe NK is coming at them from the South (as you say).
Episode 5: Final Big Battle for the Realm
Episode 6: New Paradigm of Rule in Westeros. Hot Pie is on the Troan.
I don't think there's any time for a regroup episode