Actually the Comment lines are quite robust for what they are.
To enter multiple lines in a Remark line, Shift Enter. Previous lines disappear temporarily, but show when you finish. If you open it again to edit, you can edit the whole multi-line passage.
I usually put my notes in my Global variable Event sheet, it's never that full. And always the same place when I look for them. But you could make your own event sheet.
I always have at least one "To Do" list, and 1 Error list.
I cut and paste old basic source code into them for reference when converting old games.
<img src="https://dl.dropboxusercontent.com/u/85412219/forumposts/Comments.png" border="0" />
(my comments have been always been green, hard habit to break)