An adventurer card uses only its non-Adventure characteristics in every zone except the stack, as well as while on the stack if not cast as an Adventure. Ignore its alternative characteristics in those cases. For example, while it's in your graveyard, Jidoor, Aristocratic Capital is a colorless Town land card whose mana value is 0. It can't be the target of Sorceress's Schemes, which reads in part "Return target instant or sorcery card from your graveyard or exiled card with flashback you own to your hand."