You arrive at Sultan, the town at the edge of the desert. The armor and weapons sold here are the same as in Elrand, so don't bother checking the merchants. Just pass through and take the eastern exit to enter the desert.
The desert contains a few old friends: you're going to find Dark Priests and Cockatrices again. New installments are the rhinoceros-like Bulettes and the ever-annoying ducks, which look like they've been taken directly from the original Secret of Mana. This time they carry Pumpkin Bombs, however, which deal quite a lot of damage, so try to kill these first.
If you don't want to use the area to level up your characters or continue revelling in your newly-acquired abilities, the main path after leaving Sultan continues east, south, east and into the cave passage south.
The next screen (with the cave passage you just came through in the northern wall) is a crossroads. The way east which opens up after clearing the area leads to Navarre Fortress. The fortress is not our destination and at the moment closed off just like Altena. The way south, south-east and east leads to the oasis village Deen, where you can buy new rings and headgear and get a rest if you need. You can also go there on your way back after getting Salamando.
If you go south, west and west instead (or due west if you're coming from Deen), you arrive at another big junction with one exit north, two south and the one you're coming from east. Take the south-east one, fight a last bunch of monsters and prepare for another encounter with Bill and Ben.
Bill and Ben know the same spells as last time, they're just tougher. As they counter every magic spell and level 2 tech with a Shadow Dive, make sure that your support characters only use their level 1 tech - or stick with the somewhat higher damage of the level 2 tech, but be prepared to heal often.
Once they're gone, head into the cave south to enter the Valley of Flames. The path inside is linear, as most of the exits cannot be taken yet - you are always thrown back by an explosion. The path continues south, then all the way south into the exit east, far south again (there's a flight of stairs), north-east, south-west (save at the gold statue if you like, but there's no battle ahead) and east.
You'll meet Bigieu again, and Hawk will show up and rescue Jessica if he's not in your party. Head east again to follow Bigieu. She disappears after releasing the Fire Mana Stone's energy, so you're free to walk up to the stone and meet Salamando. If you did not change your class yet, now would be a wonderful time to do so.
Once the chatting is over, backtrack your way to Sultan (stop by Deen if you did not already) and hop onto Booskaboo again. Next stop: Mintos, the moonlit city! Just aim for the central dot on your map, approach from the north and enter the river right east of it to reach the shore.