We'll be in Italy for a 16 day trip at the end of May hitting all the usuals (Venice, Florence, Rome). I was originally thinking of staying in Cinque Terre for 2 nights (Monteresso) but have realized it would overlap with both Ascension Day and Feast of Corpus. It looks like rooms are still available but I'm assuming it would be more crowded than usual. Is it worth it? Would Amalfi coast be a better use of our time? Thanks in advance for any suggestions!
Unless you had already planned part of your trip in the Naples area and the Amalfi would extend those days, then I would say "no".
Just travel time from what I assume would be Northern Italy to Naples, then a good hour a least getting from Naples to the coast would limit you to a couple evenings and one day, having to endue a long travel day back North the next. Not sure if the Amalfi would be less crowded anyway.
We spent two nights there and did the hike for one day and took train back to starting point. Wonderful views of water and villages. Start hiking early in the day and don't think you'll hit crowds too badly. Wouldn't have missed it and would do again. I can't imagine doing the Amalfi in 2 days.
I would suggest C/T over the Amalfi Coast due to the distances involved and because you'll be in Northern Italy anyway. Train connections are also good in the north to La Spezia where you'd catch a local train into the C/T.
It's about 200 miles down to the Amalfi Coast from Rome--quite a long way.