I am looking for some community advice on how to proceed with a major web site overhaul where we are moving to WordPress as our web site framework.
My organization is converting a large web site to use wordpress as a complete web site framework. Most of the conversion is straight forward, but there are a very few pages (couple dozen) which receive 99% of the hits. These pages are written in php and perform database queries, and get hit many times per second. There are numerous interlinked php libraries involved in this existing code and it is fairly complex. What is the appropriate approach to ensure that these pages will operate efficiently within the new wordpress framework, and be scalable in general?
("page" refers to a generic web page, whereas "Page" refers to the wordpress Page mechanism)
1. Reuse the code from the existing web site and place it outside of wordpress. How do I add the look-and-feel (header, menus, footer) from wordpress to the resulting pages?
2. Create wordpress Pages for each page, linking to the existing libraries. Where would those libraries reside? Perhaps in a new plugin of my own creation?
3. Should I be concerned about the added overhead of running pages with such a high server load through wordpress as opposed to having them be standalone?
4. I want to implement a caching mechanism for the most common queries (fetching the data once and creating a cached html page which is sent rather than the php page). Is this sort of html caching easily implemented using Pages within wordpress?
5. Why can I find no documentation or examples of people doing something similar? Is it simply too difficult or am I just not looking in the right places? :)