Zelda's forest aka The Legend of Zelda (1986 version) is laid out exactly the same map-wise, including similar features such as the "It's dangerous to go alone." old man in the cave. This is also the beginning of Chapter 3 called "The Legendary Legend of Legends".
Before you enter the map, you are introduced to Link walking away from the area saying to himself "Wrong Princess", a reference to Mario as well. The characters remark on him being Irish. Throughout the area, you'll find green, red and blue rupees which when picked up will convert back to golz. You can spot a fairy that spawns in random areas and will ask the leader of the party to listen, if Mike is the leader, the fairy will grant him the power "Healing Song" which heals all the party for a small amount of health.
To progress to Orcus' lair, you have to fight through a small group of Orcs that are camped outside, defeating them will grant passage as well as two chests, each containing 16x food rations and 16x water rations.
There is a secret near the edge of the water where you can spot an arrow marked on the ground pointing at a bunch of trees, follow the arrow to find a secret which contains a chest containing a Grappling hook for Francis and a small amount of rupees. Another secret can be found by going down a screen before fighting the Orcs and going down a staircase to find a chest for Nigel, containing the accessory Fairy in a Jar, along with a small amount of rupees.
In the middle of the area you can find a house which belongs to Error that has the key to a house just south of the Castle town.
Once you get to the door of Orcus' Lair, it will say the door is locked, and that you will need a dungeon key to unlock it. One of the guys in a cave sells a dungeon key for 25 golz.