Action of type A: Moving to depart from a Quest Are all the White cards played thus far on a Quest removed when the last Knight present leaves that Quest?
No, all the White (not Black!) cards are removed from a Quest only if that Quest is a Solo quest, ie Lancelot or the Black Knight’s Quest. Action of type B: Drawing White cards at the Round Table. This action cannot be chosen if you already have 12 or more cards in hand. A Knight with 11 cards in hand, may, when in Camelot, choose to draw White cards and end up with 13 in hand (or even14 if he is Sir Gawain). A Knight with 12 or more cards in hand may stay in Camelot, as long as he has a valid Action to perform there (eg fighting a Siege Engine, Healing himself, playing a Special White, making an Accusation). Otherwise he MUST move on to a new Quest.