Finally at Fourside
When you finally make it to Fourside, make your first stop Topolla Theater. You'll have to buy a ticket to get in and see the Runaway Five perform. When the show is over, head backstage and talk to the band to find out that they have been cheated out of a million dollars this time. Talk to the manager while you're there to find out more.
Before moving on there are few things you can do. First, return the contact lens to the man on the second floor of the bakery. He'll give you a Pair of Dirty Socks (not really worth it, but fun anyway). There is a man selling junk in the northern part of town. Don't waste money on the Broken Gadget, you can get it later. You can listen to gossip in Jackie's Cafe. If you head to the Department Store you'll find out that it is closed. Go to the Monotoli building next and head up to the 47th floor. You'll encounter Pokey!
Not much left to do, so head back out to the Dusty Dune Desert where you will search for a way to pay off the Runaway Five's debt once again.
 The Gold Mine
Once you are back in Dusty Dunes Desert, there are two stores that you need to purchase from. Head straight for the drugstore to stock up on Refreshing Herbs', and Picnic lunch. If you don't have the associated condiment, you can instead purchase Hamburgers from the Ice Cream Vendor. Most likely, you need these during the next dungon. You can use the duplicate item trick with the Truffle and ketchup packets to constantly have a source of regaining PP if you'd like. Make sure you level up to at least 31 before entering this mine.
Go to where the miners were digging and you'll find that they have uncovered a cave. Enter and be prepared for some difficult enemies. You'll encounter snakes and ants which will poison you regularly. Use PSI Healing and Refreshing Herbs to counter that. Have Paula use PSI Freeze to destroy enemies quickly, but watch her PP so that she doesn't run out.
From the entrance head north and take the northern split to come upon a ladder. Take this ladder down to the next level and you'll come across your first boss battle in this dungeon, the Guardian Digger. You'll fight five of these while in this dungeon and they all have the same strategy.
When the battle is over, open the present for an IQ Capsule. Head to the left and up the ladder back to the first floor. Go south and when you come to the split, take the south path. The path to the right just leads back to the entrance. Follow the southern path and you'll come across a Big Bottle Rocket. You'll come upon another split shortly after. To the left is an Exit Mouse, but don't grab it yet (that way you have more room for other items that you'll find here). Take the Croissant and Picnic Lunch from the presents nearby. This area here splits off in many directions, each leading to a Guardian Digger. You can choose any path you'd like. For the quickest, follow the directions in the next paragraph.
Head back to the right and go north. Go down the ladder and you'll see your next Guardian Digger. Take him out and grab the Coin of Defense nearby. Head to the left, grabbing the Calorie Stick along the way. Go up the ladder and head south. When you come to a split, go to the right for a Teddy Bear which will take some damage for you from the last set of Guardian Diggers. Go back south and when you reach the next split go left. There is a ladder that leads down to a Super Bomb. Go back up and to the left. You'll come upon your third Guardian Digger and a PSI Caramel. Go back to the split and take a right to come back to the Exit Mouse. Go north and take the split to the right to acquire a Secret Herb. Heading farther north will bring you to another Guardian Digger and a Guts Capsule. Go back to the Exit Mouse again and this time pick it up. If you don't have enough room, use the IQ and Guts Capsules that you picked up recently. Finally, go to the south and final split from this area. You'll pass a Bomb before reaching the final Guardian Digger. Defeat him and grab the Luck Capsule (which you should use to make more room if you need to) and Platinum Band. Use the Exit Mouse and you'll be back outside of the mine. Be sure to talk to the miner outside of the miner's shack before you leave.
Rest up at the shack and head to the bus stop or just walk through the tunnel back to Fourside.