Page Caching does not really work in this instance, too many dynamic objects and page is slow without pre-primed object caching. I did figure out a workaround off your page caching preload idea…. load the pages from a outside of word press source to prime the object cache. just wrote a php file that reads the sitemap.xml and loops though file_get_contents() for each page, run it automatically every hour with W3 cache set TTL to 7200 seconds
