Is Corinth worth a quick visit?

Getting off the main road to get a better look at the canal is well worth it, that would be relatively quick. There are ruins of old Corinth, I do not think they are that spectacular, the main draw seems to be a connection to St. Paul for many. You do not mention if you went the the ruins at Mycenae, if not, I would suggest that.

Definitely stop at the canal if you have an hour or two.

Right beside Ancient Corinth you can find Acrocorinth. Its a huge fortress with 360 degree views over the landscape. Its totally worth a stop. Some images of Corinth area.
Corinth Area. https://www.flickr.com/photos/stanbr54/albums/72157711755443483

I knew the Fourm would deliver! @Paul we did visit Mycenae, and loved it! The canal and fortress sound perfect. Now, our itinerary is more rounded out. Thanks, All!!

The Acrocorinth is spectacular. Not to be missed imo!

@edwardius I agree!! Acrocorinth was spectacular. I wish we had been able to spend more than just 90 minutes or so there. It is a huge area with gorgeous views. Definitely worth the side trip.

I have been to Athens four times and the last time did a half day tour to Corinth that included a short cruise on the Corinth Canal. It was very enjoyable. The ruins at Corinth are interesting as well.

For future readers, since the OP has already traveled through but,

Corinth has a whole lot of things to do. First, the ancient site and museum is extensive and in a wonderfully dramatic location. Above Ancient Corinth is the much-more modern castle (like, 15th Century vs. 1st Century) that is great fun to explore. Naturally, you get a history lesson at the castle, in addition to a great hike and stunning views over the entire region including the Gulf of Corinth.

Last, of course, is the Corinth Canal which is immediately on the route of any trip from the Peloponnese to Athens. We usually spend about an hour at the canal.

For what it's worth, I used to lead 17-day tours to Greece. On Day 1 we would drive from Athens to Nafplio. The visit to the Corinth Canal was a perfect first stop since it's only an hour from the city and gave my tour guests a chance to stretch their legs and see something unique.

On Day 5 we would be passing back through the area and would visit the castle in the morning, come down into the town near the ancient site for lunch, and then a visit to the ancient site. Then we would be on the road to the next overnight by about 3pm.