Camogli to San Fruttuoso
This track follows the "single red circle" trail from Camogli to San Fruttuoso in Parco Naturale Regionale di Portofino. All of the trails in the park are well marked and easy to follow, just make sure you pay attention to each sign at the trail intersections.
My wife and I chose the single red circle route since it is considered one of the easier trails to access the monastery at San Fruttuoso (my wife is recovering from a knee injury). We caught the ferry back to Camogli when we were done exploring San Fruttuoso.
The trail follows a steady climb for about 3 miles and then has a steep descent to the monastery. If you are up for it, you can hike back along this trail to add some more miles to your hike.
An alternative route is the double red circle trail, which goes around the north-western corner of the peninsula to access the monastery. I think that this trail is longer and has more up and down, but you get to be along the coast most of the way and you will get to see some WWII bunkers along the way. We were able to see this from the ferry on our way back. If you take this route, it might be best to make sure the ferry is running that day so you have a bail out plan once you get to the monastery.
The visitor center in Camogli or Portofino will be able to help you to determine if the ferry is running and provide schedules.