Nice start to your project. Typical rusted out on the lower front cowl area. Dirt and leaves get down in there and plug the drain holes and rust it out. There is a replacement panel for that rocker to cowl panel or you can make it.
http://www.ss396.com/mm5/merchant.mv...e=ROCKERPANELS
http://www.ss396.com/mm5/merchant.mv...ode=COWLPANELS
You will have to check the back lash in the rearend when you put it back together.