Hi Kelsey,
Depending on your comfort with PHP, you should be able to write something into the functions.php file of your theme by using the available hooks. You can adjust the available columns by using the ‘winbm_event_columns’ filter. Then you can display your additional column by utilizing the ‘manage_board_events_posts_custom_column’ action. You can see both of these at nonprofit-board-management/includes/class-board-events.php.
If you’ve never worked with custom post type admin columns before this article should be really helpful: https://justintadlock.com/archives/2011/06/27/custom-columns-for-custom-post-types.
As I’m sure you know, I’d encourage you not to make changes directly to the plugin files, since any changes will be erased when the plugin is updated.
Good luck and if possible, it would be great if you posted the code when you’re done in case anyone else is looking for this functionality.
Jonathan