To trigger the Hotel Booking Notifier emails do I need to setup a cron job on the server, or will the plugin automatically send any pending emails once a day?
I could not find any details about this in the documentation.
There is no need to set-up a cron job, the e-mails are sent automatically according to the set number of days before/after check-in/check-out date in the Notifier settings under Bookings ->Notifications tab. If you do not receive notifications for some reason, I would recommend that you set-up SMTP on your website, e.g. by using the Post SMTP Mailer/Email Log plugin.