OK here is my Idea ,
1. everyone makes a new char of their choice to
only be played a group on a day and time aggreed apon.
2. On this day a dm will give the group a map or maps and the group will adventure together to try (repeat try ) to find the treasure. At the end of the adventrue the dm will reward EVERYONE in it with 20 Blank Silk paper and 20 Map makers Ink so they can try to improve their chartography skill.
3. At least one char must be a rogue ( or the group will never be able to open the chest)