Creating a default Custom Post Template that a Theme can override

I’m in the midst of building a WordPress Plugin that adds a custom post type, for which I’d like to include a default template to display. Essentially, this is an event management plugin, and the custom post type is for the Events. There’s a handful of custom meta fields, as well as a child post type (Performances), so without a default template to display them, using it would be pretty unfriendly. But I would like theme designers to be able to create their own templates for these post types if desired.