To best see your entire sequence, using the \ (backslash) key does the trick.
It is the shortcut for what Adobe calls Zoom to Sequence. It does it in a way that you can see the entire timeline fitted to the panel window, with extra seconds of empty space after the last clip of your sequence.
Pressing the \ key again will bring the sequence to the level of zoom it was before your Zoom to Sequence action.
It works for both when the timeline is zoomed in or zoomed out.
The End