Just a couple more ideas. Way back, wood chips were used for insulation. To keep it from moulding and to keep insects down mix in some lime. Free wood chips are available from people who remove trees. The tree removal guy I know is always looking for a place to dump his chips. So make some calls. Also someone mentioned bubble wrap. That should work real well. Try furniture stores or unclaimed freight stores. They throw that stuff away by the dumpsterfull.
