i beat both ruby and emerald without ribbons. for ruby i used the white cape (frog/small). i beat emerald first then ruby, the good thing about that was, you get master summon from emerald, then when you fight ruby put on master summon and your other kights of the round with mp absorb, w summon, and life two with final attack. now w summon hades and kotr hades freezes him for a while. just keep w summoning kotr and you get like 1000 mp back every time ^_^.
as for getting out of the crater, when you come out of the little cave thing a the top of the big hole that goes down into the crater, climb up the rocks to your immediate right.