Word Work is a separate entity, but at your level, most kids don't need as long on that as Work on Writing or Reading. So, the Sisters suggest that the kids have 10-15 min of one writing round to do the Work Work required, and then move on to writing. If you look in your book on pages 16 and 17, you'll see the structure that the Sisters suggest for primary/intermediate classroom. One shows three rounds, and one shows two (when the students have more stamina and can handle a longer time for each reading and writing session. Notice that on both pages, the Read to Self and Work on Writing are bolded, to show that they definitely must be done every day, and in the case of the two-choice sessions, would be the main choices. If your students need a bit of word work (but not a whole round), they can do 10-15 min then move on to Writing. Make sense? This is explained in the text, as well.
Yes, choice is imperative. After you have introduced them, students can choose the order they do them.
The CCSS standards on the menu can be found here: https://www.thedailycafe.com/cafe/cafe-menus/ccss-aligned-menus
