Final Fantasy III/Tower of Owen

Inner Sea
You can for example go back to Castle Sasune and start the Fix Sara's Pendant Quest or finishing the Save the Children Quest if your level are 13 or higher. There are several places that you can visit and you should start with Tokkul. Go west the coast along to find Tokkul.

Tokkul
Enter it and go northwest to a tree (Lamia Scale). South of the tree is a crate (Great Bow) and southeast of it is another crate (Bacchus's Cider). Go east and seach the forest (Ice Staff)

Enter the northmost house and go in fireplace for 2 chests and 1 vase (Serpent Sword, Kenpo Gi and Sonic Knuckles). Exit the village and go west until yo've come across a forest with a circle of grass. That is the Chocobo Woods. Enter it and you can get a Chocobo and run around without getting into random encounter. Run once with a Chocobo around the continent to claim a prize in the next village. Near Chocobo Woods is a village.

Village of the Ancients
Go upstairs twice and go left, then north to talk with the child. He will give you a prize (Gnomish Bread), if you run around the floating continent with a chocobo and then return to him. Check the white flower (Serpent Sword) north of the well near the Inn.

Buy some Maiden's Kiss, since you'll need it soon and maybe a Light Staff, With which you can cast Thunder. Go back to Ship and sail northwest of Nepto Temple until you've across a Castle.

Castle Argus
Enter it and you'll find out it's empty. What has happened here? Go inside and upstairs. Check the fourth candle from left for a secret passage to the east. You will then come in a room with 3 chests (3000 Gil) behind a wall which can walked through. Go upstairs and you find 6 more chests (4700 Gil). Go upstairs again and go left until the door. Unlock it with a thief in your party, if you don't have one then change someone to a thief and place him at the top of the party.

Check the dresser to give way tp 3 chests (Killer Bow, 20x Light Arrow and 20x Medusa Arrow). Exit the room and go right to another door. Unlock it and you are in a room with 6 chests 20x (Book of Fire, Book of Light, Book of Ice, 20x Fire Arrow, 20x Ice Arrow and Scholar Robe)

Go back to the room with 4 candle and go upstairs. Go right from the round table and go downstairs (which is hidden). You will come across 2 chests (Antartic Wind and Bomb Fragment). Go between 2 chests through the wall to the east to a hidden chest (Artic Wind). Go back up and exit the room to the south to find 2 springs (Revive and Restore).

Now you're done here so exit the castle and go southwest to a forest called...

Living Woods
You will meet some fairies there and a crater where the elder tree was. The fairies tell you that Wizard Hein from Castle Argus came and placed a curse on the elder tree and took him. The elder tree is transformed in a castle and wander the desert near Tokkul aimlessly. They also tell you something about Hein's weakness. Now go northwest from Castle Argus to mountains. From there go on west path as the north way leads to Chocobo Woods.

Gulgan Gulch
Go on and go downstairs and talk with the man in the middle. He will give you the spell Toad which is needed in Tower of Owen, where you'll go next. He also tell that Desch's destiny lies in the tower. Go south through a secret passage to 3 chests (Fire Staff, Ice Staff and Mage Robe).

Tower of Owen
The tower is north of Castle Argus. On the first floor go around to a small room and turn your party into toads and enter the room. One floor higher turn your party back and continue west to floor 3. On half way you will hear a eerie voice who welcomes you here. On floor 3 go west of a chest (Echo Herbs) to next floor. Nothing here, so Go to floor 5. On floor you will hear a laughter from the eerie voice again. check the chests (Spark Dagger) and continue to next floor.

The eerie voice tell you on floor 6 that you'll never find the way to the place. Check the north nische to make a wall disappear. Check the chests (Echo Herbs) west of the stairs and go upstairs twice. Go right to find 2 chests (Echo Herbs and Bomb Fragment), then go left to next floor.

Go west, north, then east to find a chest (Sonic Knuckles). Go west and west again to the last floor before the boss. On this floor are 3 chests (Salamand Sword, Flame Mail and Zeus's Wrath).

BOSS: Medusa
A team of mages would be best against Medusa. Start casting with lvl 3 spells, then continue with lvl 2 spells and so on.