Stewart, there is a simple way to make the admin area present more simply with two plugins. You can certainly optimize the output of what these plugins will give you, but they can at least get you started.
First, you want to create a new custom post type. Custom Post Types UI is a simple way to create your new post type. You can also create custom taxonomies in this plugin.
Secondly, you want to customize how this new post type is presented to your user. For that, you’ll want to use Advanced Custom Fields. You will get all the custom meta boxes you want, and you can hide meta boxes you do not want. The documentation is pretty thorough and ACF Pro can get you even more specific layouts in your admin area.
For example, you want the school to be able to post content specific to urgent messages such as snow days or school delays. This content will be presented above the top navbar when relevant. Use Custom Post Types UI to create a new post type called updates. You can set the “Supports” to whatever you want. For this example, probably “title” and “editor”, but you can add in anything else you want.
To customize this presentation, you’ll go into ACF by selecting “Custom Fields > Add New”. Title it something like “Updates Content”. Select “Add Field” and you’ll create the custom admin presentation here. Title this box whatever you want, then in the “Information” and “Placeholder” areas enter the text you want to appear in the admin area. Enter any other options you want, then under this is an area called “Location”. Set this to “Post Type is equal to Update”. At the bottom of the screen, you’ll see “Hide on Screen”. You can toggle everything for this example. Instances where you need the_content() for SEO, leave the Editor active. Save this, then go to the custom post type Updates > Add New. You’ll see your custom admin content now. To display this content on the website, refer to ACF documentation for get_field().
This workflow is how we prototype projects. If you are not worried about high traffic loads on the final project, you can use what these plugins give you without a problem. If you are concerned about this, you can export code from each plugin and put it either in your functions.php file or create your own plugin.
Hope that helps. Good luck!