As a word of advice though, I would encourage you to play through the game normally first, THEN try to locate the caves, unless you're truly too stuck to continue. Like I mentioned, Goodie Caves make gameplay easier, and can take away from the richness of gameplay that can come from trying to figure things out on your own.
The following are locations to get to the various Goodie Caves in Aveyond: The Lost Orb:
Note: I am only posting locations of the Goodie Caves and general directions; if you would like a picture of where the goodies are located, please visit www.amaranthgames.com-->community-->AV 3-3: The Lost Orb-->Maps, Guides, Etc. All Goodies are marked with great subtlety on the maps corresponding to the Goodie locations listed below. More specifically: (Highlight for Spoiler): Goodies are marked by a small dot, in this case either black, white, or a pinkish color.
Gives 600,000 GP
Location: (Highlight for Spoilers): Peliad (The forest right of the cemetery and in the upper left-hand corner, by the city walls).
Gives all the best weapons in the game
Location: (Highlight for Spoilers): Bristle Woods East (From Peliad, Northeast and in the area near the broken bridge to Tyobi)
Gives level gains up to level 99
Location: (Highlight for Spoilers): Bristle Woods West (From the Ferry Station, go north, then east at the first turn, passed the signpost. Goodie Cave is in one of the trees.)
Gives the best armors in the game
Location: (Highlight for Spoilers): Blueleaf Forest (From Harakauna, go down the stairs immediately south and check all around this area.)
Gives the best spells in the game
Location: (Highlight for Spoilers): Wyrmbone Desert (From Tyobi, travel partway towards the Root System [which is accessed via the Great Tree]. Once you pass the waterfall to the west [as you are heading south], head west over the bridge and keep heading west until you come to an alcove in the cliffs.)
Gives all recipes in the game
Location: (Highlight for Spoilers): Worm Tunnels (From Tyobi, go south and northeast up two staircases to exit 1. Go up the stairs to exit 2. Go south, west, and north into the tunnel. Go west and northwest, then check along the wall leading west.)
Those are all the goodies available in Aveyond: The Lost Orb! Again, as a warning, using these goodies will make gameplay drastically shorter, so if you want to get the most of your gameplay experience, I advise you to not use goodies until your next play through.
Till next time, folks!