My two cents: I have done both what Mark suggested and what you have started. The reason originally did it the way you did (sections, form rules to hide things etc) is the same reason you did - navigation is much nicer, especially on mobile (where my checklist was being used).
However, there is a reason Mark does not recommend the design, and I now agree and have stopped building it the first way. Having a child table with your checklist items will, down the road, have many advantages. As you go down the rabbit hole of wanting more metrics and charts, the child table will be invaluable. Additionally, if you ever decide you want to add notes or pictures for each checklist item, you will be very happy it is in a child table.