Rossiter's older guidebook (Boulder Climbs North) gives a description of Stairway to Heaven. The route gets the "quality star" and is made to seem enticing. Rossiter, in particular, praises the "exquisite ridge" leading to the summit of Like Heaven. The Guardian is also described in the older book.
If you look at the index of the newer Rock Climbing the Flatirons, you'll find that both Stairway to Heaven and The Guardian should be found on Page 153, where the list of routes, however, stops at number 15. Maybe a late editorial decision, not well implemented, or just a composition problem that led to an unplanned omission.