Hello,
I have checked all provided details also seen example of calendar that you have provided and wanted to confirm you that I will do all modifications to TravelPress WP theme and add more tab where it will be calendar with dates when trip is starting according to you.
As I have extensive experience with Wordpress, PHP, MySQL, HTML5/CSS3/jQuery, I am also expert at theme development, plugin development, PSD to WordPress, customization of WP core for development of custom modules.
Regards,
Kaushal