We have 3-4 days with a car to explore the Tuscan coast. We would like to be based in a town so we can walk to food and drink in the evening. Ideally we would like to have an ocean view from our room and a lively but not overly crazy town! I don't think any of the towns we are looking at would disappoint but we are open to suggestions! .Castiglione della Pescaia, Talamone or Porto Ercole? BTW it will be at the end of May 2025.
We’ve been based twice in Castagneto Carducci. It’s just inland from the coast, so there’s Donoratico, at the coast. A livelier town, on the coast a few miles to the north, is Cecina.
I’m not actually familiar with the three towns you’ve mentioned, but I wanted to let you know about the ones I just mentioned. As you said, the area won’t disappoint, in any event.
That is the best part of the Tuscan coast.
I usually stay at Porto Santo Stefano (on the same Argentario Peninsula as Porto Ercole but on the north side). The reason is because it's convenient for the ferry to Giglio island (about 45 min away), which is beautiful, and also because I always stay at this hotel
https://www.hvittoria.com/
(note that their best rooms are not necessarily listed online, but they always have them when I call).
In terms of convenience it really depends on where you want to explore and where you find the most suitable accommodations. But it doesn't take long to drive anywhere along the Maremma coast from any of those towns. For example while in the location at Porto Santo Stefano above, I drove to Massa Marittima and Capalbio (two famous hill towns nearby) and also Talamone (which is probably the most ancient town and Etruscan and Roman harbor in that area).
I've stayed also in Castiglion della Pescaia in the 1980's a couple of times. In those years, Roger Moore (James Bond) and his wife at the time (actress Luisa Mattioli) used to be there all the time as they had a beach house in town at Roccamare (a VIP area full of fancy villas there).
Below is a useful website for the area:
https://www.tuttomaremma.com/en/