I still have my garden map from 1995, done on graph paper and then pieced together as gardens expanded. That winter I allowed myself crayons and scissors and added tiny plant photos from catalogs. By the following year I was using White Out for those plants that had to be moved, or died. It was great fun and I'd never discard it since it holds so many fun memories for me.
The only time I used a ballpoint pen was for the "permanent" plantings: big mistake! A storm took out an Acer Negundo and an 'Aristocrat' Bradford Pear (both were improvements to the gardens!) and other storms took out other trees.
Your article is very good and it is a very worthwhile project.