My husband, the model railroader, uses the plaster coated gauze that doctors use for casts to build mountains and tunnels. It is flexible when wet and will drape over anything. You can paint it with anything you want when it has dried and hardened.
PS if you have any model railroaders in your congregation, they would probably LOVE
to show off their scenery making talents.
Lisa
You can find a more detailed discussion of "Empty Tomb" building techniques in our Empty Tomb Stories Forum!
If you have more to add on this subject, post it there!