Fabulous place with wonderful views and lots to see. Don't bother to take a trip, just go for a walk up above the town and look down. The castle is very worthwhile with nice gardens and exceptional views.
We moored in Portoferraio and had a lovely day walking around this pretty old town. You get some great views if you walk up the hills above town and see the views along the coast and over the harbour.
We visited Calvi, not Ajaccio, and it is a superb, beautiful little town with a lovely harbour and fascinating old town. If you have a day here, you do not need to take a trip, just walk around the harbour and old town