With my lo, after we had been on easy for a few weeks, I found that we could deviate from the routine on some days without affecting her the rest of the week, but it seemed to depend on the activity.
We were booked in for a set of swimming lessons that fell right in the middle of nap time. She is fine for these, and it doesn't seem to disrupt other days or naps at all (she has a really good sleep in the afternoon though!). But I had to give up a mother and baby group that fell in a nap time as she was grisly and wanted to go to sleep rather than socialise...
I usually don't worry too much now if she loses a bit of one nap during the day (she's not great at sleeping in the buggy - too nosy!). She will make it up on the next nap, and on the whole EASY makes Daisy more content, meaning that I have more freedom, not less.