I’m also using W3 Total Cache on most projects. There isn’t much to it after setting up, just make sure the client knows how to empty cache if some changes are made and they don’t see them show up. Also when updating and installing plugins, you need to empty the cache.
When setting up, I just follow the instructions provided – minimizing and caching whatever possible. I’ve also used a CDN with it on my site and it speeds things up significantly.
This can be done, no code modification needed. When you’re in Appearance > Menus, click screen options in the upper right, check the posts box, and you should now be able to choose from your posts to add as menu items.