Hi @nspeaks, welcome to the Caddy community!
Please note that server configuration for WordPress multi-site installations varies slightly depending on how you choose to configure it.
You can follow the instructions from the developers to set up your multisite installation: Create A Network – WordPress.org Forums
When you get to the stage that requires you to add .htaccess configuration, if you’re having trouble adapting those to Caddy configuration, you can go ahead and post the .htaccess config you took from your site, as well as what you’ve attempted to convert, and post them here. With luck someone will be able to help you over the line from there.