The following is a list of places, and the recommended levels that most of your party members should be at before going there. This information comes straight from the instruction manual.
PLACE
LEVEL
PLACE
LEVEL
Aliahan
1
Dhama
20
Reeve
3
Tower of Garuna
21
Tower of Najima
4
Muor
21
Enticement Cave
8
Pirates
21
Romaly
10
Jipang
23
Kanave
11
Tower of Arp
23
Noaniels
12
Luzami
23
Village of Elves
12
Navel of the Earth
27
Cave
13
Samano
27
Tower of Shanpane
14
Cave South of Samano
28
Assaram
14
Phantom Ship
28
Isis
15
Cave of Necrogond
32
Pyramid
16
Liamland
34
Portoga
17
Castle of Baramos
34
Baharata
18
Tantegel
35
Cave
19
Kol
36
Shrine South of Portoga
19
Hauksness
37
Tedanki
19
Cantlin
38
Lancel
19
Ridmuldar
38
Eginbear
19
Cave North of Tantegel
39
Field (New Town)
19
Tower of Kol
40
Village of the Soo
19
Rainbow Bridge
43
Shoals
20
Castle of Zoma
44
Greenlad
20
Experience Gaining Tips
The easiest way to gain exp. is by fighting metal slimes and metal babbles. I have listed here the best places to get exp. at different levels.
Levels 1-19
Gaining levels shouldn't be too much of a problem now, just follow the above chart and get up levels around the nearest town.
Levels 19-34
Once you have the ship, go west from Portoga until you see land, head up the coast and go by the new town. Keep going north to the tip of the continent. North is the island of Greenlad and right below that is an island with a shrine that has three travel doors. This small island is the place. The enemies here might give you a little trouble at the lower levels, but once you reach level 23, they shouldn't be a problem. The main thing is that at night, metal slimes appear frequently here in groups of 2 or 3. (To keep it night, get the lamp of darkness in Tedanki, and keep using it every time day breaks.) Just attack the metal slimes with weapons (only the BEDRAGON and CHANCE spells will have any effect on them, so forget about spells at these levels). They only have about 4HP each, and you will only do 1 damage point per hit. If you do a critical hit, or if the poison needle works, they will die instantly. You will net over 1,000 exp. each for every metal slime you manage to kill. Rarely, you may meet a lone metal babble here, but chances are, it will run away before you can even hurt it. Metal slimes are very weak attackers and know the blaze spell; metal babbles are also weak attackers and know the fireball spell. So, they can't do much damage at all, NEVER RUN AWAY FROM THEM!! (unless, of course, they brought friends (other types of enemies.)) They are much more afraid of you than you are of them!
Levels 34-40
Northwest of Ridmuldar is an excellent spot. There are metal babbles here. The other enemies that appear shouldn't be TOO hard to kill at these levels. If there are more than 2 metal babbles that appear, cast BEDRAGON. This will take one round to cast, but the next round, you'll wipe them out. If you know CHANCE, cast it no matter how many there are (although this is kinda risky, because CHANCE sometimes gives bad results, but sometimes it will defeat them instantly!). Otherwise, just attack them. A Metal Babble gives over 12,000 exp. to each party member.
Levels 40+
The 1st and 2nd floors of the Tower of Kol contain metal babbles and other enemies, which also yield a lot of experience points.