After you escape from Moonside, several people talk to you outside.
Meet new People
When you leave the storeroom, Apple Kid calls to tell you that he invented a Trout Yogurt Machine, and will have it delivered to you. After you leave Jackie's Café, talk to the burnt monkey, who says to go to the desert to meet Talah Rama. After that, a delivery man says he left your trout yogurt machine in the desert. Then Monotoli's maid says that she wants some trout yogurt for Monotoli's "special guest".
Go to the Desert
The desert is your next destination, but before you go there, be sure to get the Pencil Eraser from Escargo Express if you don't have it.
If you don't want to get the optional items in the next area, and just want to get through it quickly, be sure to go to the Fourside Department Store and get a Protein Drink from the shop next to the Tool shop.
Then go to the southwest of Fourside and check on the bus stop sign to go to the desert. Enter the Drug Store near the bus stop, and buy a Skip Sandwich and Picnic Lunch. If you want to skip optional items in the next area and get through it as quickly as possible, then if you don't have a Ruler (which can only be purchased in Burglin Park in Twoson), you should also buy a Wet Towel here.
If you didn't get the Pencil Eraser from Escargo Express earlier, do so now. Also, you might want to store things with Escargo Express so that you have at least five or six free slots in your inventory.
Then go outside and go north to the ladder in the desert. Go down the ladder to enter the Monkey Caves.
There are no monsters in this area except for a few weak ones that always run away from you. If you accidentally bump into one, you can choose Run Away and it will always work (or you can just fight them).
In this area, there are monkeys blocking the doorways. Each monkey wants a specific item. The monkey will move out of the way after you give it the item that it wants.
If you want to get through the area quickly and are skipping optional items as mentioned above, then talk to the monkey on the left in the first room, ignore monkeys asking for hamburgers, and don't give Pizza to the girl monkey.
If you do want the optional items and you only brought a Picnic Lunch and a Skip Sandwich, you can find all of the other items for the monkeys in the caves themselves. However, when you find monkeys that ask for Pizzas, be sure to give it to the girl monkey first, then go through the door behind her to find another Pizza. If you give the Pizza to the wrong monkey, and you are out of Pizza, then you will have to leave the cave and go to the drug store and use their phone to call Mach Pizza and order a Pizza, which will take a few minutes to arrive. If you don't have Mach Pizza's phone number, then you will have to take a bus to Threed and go into the pizza place and talk to the person behind the counter there. So be sure to give the Pizza to the girl monkey first!
Otherwise, just talk to the monkeys and give them what they ask for. If you don't have what they need, try another route.
There is a monkey in the caves who gives you Fresh Eggs. You will need to give a Fresh Egg to one of the monkeys, but if you take too long, the Fresh Egg will hatch into a Chick. You can find the monkey that wants a Fresh Egg if you go back to the first room of the caves and go through all the monkey doors on the right. Then you can find the monkey that gives Fresh Eggs if you go back to the first room of the caves and go through all the monkey doors on the left. Be sure to plan your route so you can deliver the Fresh Egg before it hatches.
Other items that you can find in the caves (that you don't have to give to the monkeys) are a Bag of Dragonite, a Neutralizer, a Fire Pendant, and a Broken Tube.
Eventually, you find a door blocked by a pencil statue. Use the Pencil Eraser to make it disappear (if you don't have the Pencil Eraser, you will have to leave and call Escargo Express to get it) then go through the door.
Talk to Talah Rama to receive words of wisdom and the Trout Yogurt Machine. Then open the chests nearby to get a Brain Food Lunch and a Cup of Lifenoodles. Then talk to the other monkey, who will go outside to wait for you.