Leave images, cache, metadata, and transcode blank. They will default to a folder under the config folder. You only need to specify them if you want them in a different folder than the defaults.
As long as your config folder is in your cache drive, you're good.
As for install folder, is on to leave that under usr/local/ because the actual install files are stored in the USB, so they don't get downloaded each time, only once. If you want to move install folder to your cache drive, that will work also but you don't need to.