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 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