I am not sure if my advice will be helpful since my daughter is 22 mos, which is a bit younger. However, we just went through 1 month of little to no napping and it was driving me nuts. At first she would play in her crib for a few hours, which was fine by me. But then, she started to scream whenever I put her in the crib and this would go on for an hour or more. That was unacceptable since it was not restful for me or her. We skipped nap for about a week and I noticed that her separation anxiety got really bad and that sometimes she napped at 5pm when I picked up my husband from work. By the way, she would not nap if we just stayed home around 5pm, even if we were doing a quiet activity.
The week off of naps made me realize that she was too young to stop napping. She is now napping most days (today she did not, but this is the exception, not the rule). The point of my post is to say that if she stops napping and you notice a change in her behavior or she seems sleepy late in the afternoon if you take a drive, then she probably still needs the nap. If she does not get tired in the afternoon and her behavior stays consistently good all day, then she can probably just do quiet time without a problem.