For the rear support, I made a shelf area out of 1 X 6 pine. You'l notice that I cut away much of the damaged rear apron, looks much better.

Finished view of the rear, after sanding and buffing. A couple of rear lights from Wal-Mart and the CA plate from a flea market finish it off.

Front view. I also added drink holders out of a boat catalog. Painting the underside black seemed like the right thing to do.

Side view. Maybe a nice set of wheels and tires at some point? It's up to you.