Two variants that use Crown but nothing else from Adventures or Empires:
Play Crown1, choosing Crown2
-- Play Crown2, choosing University
---- Play University, gaining Mandarin, putting Crown1 and Crown2 on top of your deck
---- Play University, gaining Cultist, trashing Cultist with Watchtower, drawing Crown1, Crown2 and one more card
-- Play Crown2, choosing Crown2
Play King's Court, choosing Crown
-- Play Crown, choosing University
---- Play University, gaining Mint, trashing Crown
---- Play University, gaining whatever
-- Play Crown, choosing Graverobber
---- Play Graverobber, gaining Crown, putting it on top of your dck
---- Play Graverobber, trashing Cultist, drawing 3 cards including Crown, gaining whatever
-- Play Crown, choosing Crown
(alternatives: have enough Throne Room variants to play a drawing action between the Graverobber and the second Crown; have the +1 Card token on Graverobber so the second play draws the Crown whatever)