When you're scheduling, only click on one day per week as your day(s) of choice. Then add your divisions by chapter. For example, if you're wanting to read one chapter of Stuart Little per week, you could schedule it on Mondays. Once you finish each chapter, click on "Finished". It won't be back in your Daily Plan until the following Monday, until you're finished with the entire book.
If you schedule Stuart Little and decide you want to read Charlotte's Web as soon as you're finished w/ Stuart Little, then you click the "Start After" option in the Scheduler. And then click on Stuart Little. Charlotte's Web will automatically come up in your daily plan as soon as you complete the last chapter of Stuart Little. And then you continue just like you did with Stuart Little. (I don't know how old your children are. I'm using those books as an example because we're reading Stuart Little right now )
As far as "complete as own pace", I believe that's what the "Worked On" feature is for. You don't have to finish an assignment everyday. I hardly ever click on "Finished" daily.
The Scheduler does allow you to schedule specific assignments/chapters for specific days, just not weeks. If you want to schedule one resource after another or use one resource with another, you just specify "Start After" or "Use With" on the Scheduler.