Peljesac is about 70km long and 8km wide, and I really like to drive the route from Ston to Orebic because there is so much to see. The road sometimes go high on the mountains and from there it is great views and then down towards sea level again and then up through the pine-covered mountainsides and it smells so incredibly good about them, then you can hear cicadas everywhere.
And so there is grape farming everywhere and signs showing all the wine tasting places so just choose. my favorites are Dingac and Grgich.
The road is quite narrow and steep in places, so it can be scary to drive there. :))
Then you can always take the detour to all the small villages that are almost everywhere by the sea, maybe eat some good food and then sunbathe, swim. We usually do that.
From here you can also take the ferry to Mljet, is an island just 5km away and they have a nice National Park and it is worth a visit. Or you can go all the way to Orebic and take that ferry to Korcula, which is a bit like a mini version of Dubrovnik. Well worth a visit too.