Costa del Sol is actually located in the “Corel Area” region when you check your menu screen. Mount Corel is your next destination.
Mount Corel is due west on the world map from Costa del Sol. You will have to start off by traveling south first and then traveling into the mountains.
The pathway leads you up through a mountain path. Enter through the small cave at the end of the mountain path and in to the next area.
The man sitting on the rock pathway will tell you that he saw a man wearing a black cloak pass by. Continue along the pathway until you reach the Corel Reactor (shown in the screenshot below).
Take the pathway all the way down to the reactor and walk along the train tracks leading to the bottom of the screen.
Continue following the train tracks in the next area; do not jump down onto the stairs or go down to the lower level as there is nothing to do down there.
Use the 
Save Point in the next screen to save your game as there are some weird / difficult challenges coming up which might catch you unprepared.
Jump over the hole in the track. The track splits just after the hole into one track that goes upward and one track that goes downward. Take the path leading upward and be prepared for an upcoming surprise.
As Cloud walks to the right a portion of the track will give way and Cloud will fall through the opening. Hold the 
(Left) Button on the directional pad and press the 
Button as many time as you can. This will cause Cloud to drift to the left as he falls.
Climb back up the scaffolding and, if done correctly, Cloud will pick up an item bag containing a 
Wizard Staff for Aeris.
Continue to the very top of this pathway and open the treasure chest to receive a 
W Machine Gun weapon for Barret.
Travel back to where the tracks split and take the lower path. The tracks will give way again as Cloud passes over. Hold the 
(Right) Button on the directional pad this time and press the Button (or the 
Button in the PlayStation 4 version of the game) as many times as you can.
Cloud will pick up an item bag containing a 
Star Pendant on his way up this scaffolding section.
Backtrack after you reach the next fork in the pathway and take the upper pathway to pick up the 
Turbo Ether sitting on the track.
Cloud will fall through one more time as he walks towards the Green Materia that’s visible on the track. There will be no other items to pick up if you already grabbed the W Machine Gun and the Star Pendant so, if you’re quick enough, press Button to jump out of the way before the track breaks.
Grab the 
Transform Materia on the upper track and then continue eastward down the tracks. Take the upper pathway at the next fork.
Cloud will appear on the upper level of the tracks. Continue to the east and follow the track around. Continue past the small shack and follow the track until you hear birds start chirping. Climb the pathway upwards to reach a birds nest.
You will have the option of taking the treasure or leaving it where it is. If you take the treasure (10 Phoenix Downs) you will have to fight a Cockatolis enemy.
Enter the shack at the end of the pathway and have Cloud turn the lever/knob. This will cause the bridge on the lower track to drop down allowing the team to cross.
Cloud, on the other hand, will have to travel all the way back around with the rest of the team. Travel back to where the tracks split and take the lower track. Follow the rest of your team around the lower track that runs underneath the shack.
Follow the tracks leading off towards the water down below and follow it around to the right. This pathway will lead to a cave with a Power Source, Mind Source and a Tent inside.
You can talk to the miner to hear his story about not having a job. Exit the cave, head back to the upper track and follow it around the bend to the right.
Cross the huge rope bridge to reach North Corel town.
North Corel is Barret’s home town. Move towards the center of town to initiate a short cutscene involving Barret and the townspeople. There is an Item Store that sells the following items:
The Weapon Store sells the following:
Carbon Bangles
Force Stealer
Molotovs
Unfortunately, nothing particularly useful at this point.
There is an Ether hidden in the tent on the right - you will have to wait for the woman and old man to move out of your way before you can grab it.
Take some time to exit the town by following the exit sign on the right side to find yourself on the World Map. Saving can be difficult in Gold Saucer, your next destination, due to the lack of ‘free’ Save Points so save your game now while you have the chance.
Go back into Mount Corel from the world map and find the pathway leading to the left out of the town center (with a big sign in front of it that reads “Gold Saucer”). Follow that sign into the next area.
This is the tram that leads to Gold Saucer but, before you can board, Barret will give you some background about why the people of North Corel despise him so much.
Head to the next page once you reach Gold Saucer.
