There are multiple ways to do this - each with their own + & - points...
You've already discovered the 3 column approach - with the negative that you have to be precise in how much you write into column 1, and then, if you change anything (font size, column width, etc) it could all go wrong (like if you send it to another computer that is set up as 'Letter' by default.
So, the way I would choose is to make a three column table, then change the line colour to Blank (sic) or White - that way, if anything resizes, then the columns will also continue properly. Now you can draw lines across the two columns, then you can drag them if needed to align them with the text in column one.
With a little bit of practise, you can get it all working well.
One tip (IF you use this method).... Alter the colour/transparency of the table AFTER you have finished aligning the text! LOL!