At Ajaccio you can bear to the left and stroll through the town, visiting the market in the square and then walk around the headland to the lovely beach which is just a few minutes away.
The ships dock right in the middle of Ajaccio and tender just of Villefranche and thus it is easy to walk around both or if one wanted in the case of Villefranche het a train along the Riviera to Nice, Cannes or Monte Carlo - proviced you have the time! Santa Margharita is another tendering port and it depends where you are landed - there ot Portofino. By the way all three are wonderful places to explore by foot and you would undoubtedly enjoy.
If you decide to go under your own steam then at villefranche catch the bus to monte carlo as is only 1 euro..