It should be nice to cycle. The rental in Mörbylånga is right by the bus station, so if the wind is blowing from the south, you can take the bus southwards, i.e. into the headwind and then you get a lovely bike ride in the tailwind back to Mörbylånga. And if it blows from the north, you can do the opposite. The buses normally take 2 bikes.
From Kalmar, you can take the Dessi ferry over to Färjestaden to start your cycle tour. You can also do the opposite, and start from Öland but take Dessi across to the mainland. See when the ferries depart on the Dessi timetable.
Learn more at Kalmar Länstrafik