I'm coming up dry on destinations for a solo vacation in early September, and I'm hoping for some ideas! I'm looking for a place where I can relax on a sandy (not rocky) beach and read a book for hours and splash around in some warm water, with easy access to facilities should I get hungry or need a bathroom (i.e. ideally my hotel would be on the beach itself). At the same time, I'd like the option to go to museums, see historical sights like old church or castles or ruins, and go out for delicious dinners. I'd rather have those excursions nearby so I can do them for just part of the day (i.e. not have to take many-hours-long train/bus rides or stay overnight elsewhere).
I'm an early-30s female solo traveler from New York. I'm much more into relaxation and culture, and don't care for nightlife/bars or adventure sports. I only have 9 or so days and so ideally my transit wouldn't require too many transfers (being on the go the whole time would defeat the purpose of a relaxing getaway!). And though I'm adventurous and live in a big city, I'd like to feel reasonably safe and not be harassed too much.
Any ideas for destinations would be greatly appreciated!