Mushroom Rock Road

After following Seymour through the gate you'll have another chat with him. Afterwards talk with the crusaders along the path to get a Tough Bangle, Remedy, Ether, 2 Phoenix Downs, Hi-Potion, X-Potion, and 400 gil.

The path north is blocked by Clasko so take the left path. O'aka is here with a generous inventory. Then continue past him.

The guard before the lift hands over a Hi-Potion. Take the lift. Keep going through the next area until you find a guard standing next to a chest. The chest holds 1000 gil and the guard gives you 10 Potions.

Continue along the path to the chest with a Remedy. Also, Shelinda stands nearby and can restore your party's HP & MP.

The next chest is partly hidden behind a rock pillar. It contains a Hi-Potion. Then continue to the next lift. At the top go left to another lift and take it down to get a Serene Armlet.

Back at the top you'll have to navigate over to a ledge on the left. Here you'll find Al Bhed Primer Vol. X. Then take the last lift up. Now go right to a machina platform. The guard here will give you a Mega-Potion. Then go past the save sphere to overhear a conversation between Luzzu & Gatta. Talk to Luzzu and then ride up to the command center.

Continue through the area until you come across Gatta. You'll get some options during the conversation. The choices you make here will determine Gatta & Luzzu's fates.

After this you'll meet Maester Kinoc. Then get the two treasure chests for a Mega-Potion and a Serene Bracer. When you're ready for battle talk to the guard marked on the map.

This battle has two parts. For the first part you'll want to make sure everyone in your party gets involved so they'll get some AP. You'll need to start out this battle with long range attackers like Lulu and Wakka. Lulu should know all the second level spells. This boss has four parts - the head, two arms, and the body. The arms protect the body and the head does a nasty venom attack. You'll want to eliminate the head first using Wakka and Lulu. Then you should bring in piercing hitters like Auron and Kimahri to take out the arms. Lulu can also help with her spells. While the arms are gone (they will regenerate) you should attack the body with everything you've got. Once the body is defeated the battle ends. The second battle your only party members are Yuna, Auron, and Seymour. Use the same tactics as before and this battle should end quickly. As a reward you'll get lots of AP and 6 Lv. 1 Key Spheres.

After the battle find Luzzu or Gatta. Then pick up the Hi-Potion from the chest. After talking to everyone head up to the next area.