All you need is a section of brown craft paper, texter and your imagination! This is a fun open ended play idea with enormous potential for imaginative play. This doesn’t have to be an actual treasure hunt (although that is fun too); my daughter played independently and created her own imaginary treasure.
I always have a roll of brown paper handy (you can get rolls from places like BIG W, Officeworks, Spotlight etc). I wrap most of gifts in the paper (decorate with ribbon, twine, or get the kids to draw on it as decoration) and cover school books too.