Yep that is the way I would have suggested to do it. Create a main slide with the calendar then link to each slide with the event for the day. Include some animations or effects on each day slide to jazz it up a bit. I've used this technique with students and it's really only limited to your imagination.
Include a "home" button each of the individual day slides so it allows you to navigate back to the main advent calendar slide.
You can use the Slide Master to set up some master elements such as how the heading is formatted, the date to display and include the Home button and then just add the content for each day as required.
Not sure which slides you are hiding or why but I've got a sample file I've created in this exact method to create a boardgame and when I save as PDF the hyperlinks still work.