When an attack is undefended, the damage go to these locations if they are in play.

Question is: if damage is higher than their quest points? Do you place anyway the excess damage on them or must you deal excess damage on a hero?

The HoN rulebooks says : "When quest stage 1, The Defense, is active, damage dealt to the lowest threat location from an undefended attack does not carry- over to the next Battleground location. " I'm guessing it doesn't cary-over to a hero either, it just gets removed from the game.