Just thought about creating a thread that would help everyone have a easier time to progress in the game (feel free to contribute):
-You can fight 1 Zeon over and over in the first part of chapter 1. Doing this will help you buy all the supplies you need for the next part.
-Between Wendala visits to her masters, you can train, earn money and buy supplies or equipment. This will make your progress MUCH easier than relying only on your treasure hunts.