The calendars are great, however It would be great to have a single calendar, that you can update with a prev - next buttons somewhere and save space.
There is code in the issue queue to demonstrate how to achieve this functionality with jcarousel etc.
What you're asking can be done at the theme layer.
If you want to use your own calendar logic have a look at hotel_booking_preprocess_node to see how to add in the calendars before the node is shown. You can implement this in your theme (copy the function and rename the function to suit your theme name).
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