I think your summer program looks fine. It's a pretty basic sprinter summer program (proposed by mike I believe?).
One thing you might could look at is the UW-LX program posted in the "Hypothetical Thought" thread in the Classics forum. It starts off with lots of tempo and strength work early which is just what you might need for the 400h and open 400. Plus, with the great base it provides, you should really be able to open up and tap into some hidden speed you got as well seeing as how fit and ready to go you'll be. Just a thought…