Hint: Castle Island:
Go to Darren's house and find the Hospital page in the backyard. Go to the Hospital's mailbox. A patient will give you a ticket to Castle Island. Go to the Ferry Pier to go to Castle Island.

Hint: Skateboard:
Go left from your house to reach the intersection. Next, go down across the road and keep going in that direction. At the corner, go right. Keep going until the Brickster gives you a skateboard. Hint: Wrenches:

From the "man fixing car".
From the radio man.
Go south from the tunnel leading to the south part of the Island.
Near the farm at the south part of the Island.