Not that I tend to use the tube much at peak time, or ever really. However I still found this info and map very helpful to decide the delicate balance between using your legs, or putting up with over crowding at key stations on the tube.
My office is on Trafalgar Square. I have at times directed people to Leicester Square via the Northern Line from Charing Cross using the Bakerloo Line entrance in Trafalgar Square. Other times I have directed people to Covent Garden by using the same directions for Leicester Square then advising them to change to the Piccadilly Line for the single stop to Covent Garden.