Help laying out columns

Site URL: https://corn-apricot-zn88.squarespace.com/

https://corn-apricot-zn88.squarespace.com/portfoliodetails/lincolnhs-c2r3k

Password BA47

I am trying to do something a little difficult.  I need three columns, like I have. but ideally we would like a 3px yellow line on the right of the first column. or make it narrower. 

I did do it originally with code on this page: https://corn-apricot-zn88.squarespace.com/fire-station-5,  BUT I need something easier as we are are handing this over to other people to input the many projects. OR I need to be able to take the other text block and make it move left to align to the width of the image. 

Ideas??