->No<- equal columns height needed

Hi all, I uploaded an image for a better understanding. I want the right column look alike a sidebar; but more content I place in the left area higher is the right one. Is there any way that right column get shorter than the left one? I want to avoid to set white background to the right column and increase down margin to move end up, both options creates a huge white space on mobile devices.

This is a trip file; I have many and any right column will be different according to the location trip and dates, so for that I prefer to avoid to have many widgets sidebars (and I'm not sure I will be able to get the same looking design).

Thanks in advance