So it took me a while, but I finally figured out how to get from the main site to the meta site using the new toolbar: one first clicks on help, and then the meta button appears. However, I am yet to find out how to get from meta to main using this tool bar. Any hints?
In the StackExchange dropdown menu on the far left of the toolbar you will finds links to main and meta (regardless of where you're at). It took me a while to find them too.