I think I’ve gotten the machine translation working to a point of good stability. Meaning my MySQL config is not killing the box with requests, caching seems to be working fine.
Right now I have 65 translated pages in my database. When I encounter one that is munged (meaning the database timed out) I manually delete that page in the ATPP cache and only that page. So fare so good.
I combined ATPP with WP-CACHE and all seems right in the world.