Shortcut to widget/sidebar editing on the admin menu?

I think that using standard WP featurs there's no shortcut. But you can workaround using a custom widget.

As example create a very simple widget, something like:

class MyPageWidget extends WP_Widget { function __construct() { parent::__construct( 'MyPageWidget', 'My Page Widget' ); } function widget( $args ) { $page = get_page_by_path('sidebar-page'); if ( ! empty($page) ) { echo $args['before_widget']; echo apply_filters('the_content', $page->post_content); echo $args['after_widget']; } } } add_action('widgets_init', function() { register_widget('MyPageWidget'); } ); 

This few lines of code, add a new widget for your site, with no options, it simply display the content of a page that has the slug 'sidebar-page'.

Now where you have your text widget, replace with this one.

Create a page and assign the slug 'sidebar-page'.

Now everything you add in that page is displayed in the sidebar: edit a sidebar widget text is simply as edit a page, in effects, it consists in just edit a page.

Widgets are not really meant to be frequently edited. They are semi-static content meant to be configured on site setup and more or less left alone. If you have built a site that requires frequent widget edits, you've probably made a bad design decision. Without knowing the details of the project, it is hard to say.

One thing that you can do to reduce the confusion is remove the widgets your client doesn't need.