http://www.pelicanparts.com/catalog/shopcart/9144/por_9144_chasis_main.htm
The longitudinal runs from the rear wheel well all the way to the front wheel well. There are more parts that cover the areas of that assembly that make the turn and head upward toward the rear shock mount. Check the pics on the page linked above (click where it says "pic") to see what parts you may need. Keep in mind that it is very likely that there is more Bad Stuff hiding that you have not found yet.
--DD