Go to Stormbend and speak with ship merchant (the bald man). Purchase a canoe for 200 GC. Walk to the river in Sinoa Plains and you can find it there. Get in and the canoe will take you to a small island. Collect the treasure and get in the canoe again. It will take you directly to the bomber egg.
There are a total of five Goodie Caves in walls at several locations. There are no visual clues on the outside of the walls that hint that a cave is inside, so you must find them by exploring and bumping Mel into all the walls. Each cave has items and/or upgrades for a specific element. There are blue chests in some caves that will be accessible in Gates of Night. Some of the items in the caves cannot be found be found elsewhere. The following caves are located at the corresponding locations:
Armor Goodie Cave
In Thial Mountains North, slightly north of the entrance from Istir Forest. It contains the best armor for each character.
Gold Goodie Cave
In Brightwood Forest, slightly to the right to one of the small waterfalls. It contains 600,000 gold coins.
Level Goodie Cave
In Shadow Woods North, left of some stairs near the middle of the woods. It can increase the level of characters to the maximum of 99.
Spell Goodie Cave
In Stormbend, close to the ocean behind the chest. It allows Stella to learn all available spells.
Weapons Goodie Cave
In Thial Mountains South, slightly north of the entrance when entering from Shadow Woods South. It contains the best weapon for each character.