This place is called Coeden Afal. It's a converted barn, so it's detached and stone-built. It's in St Ishmael, Carmarthenshire. Quiet spot, near the water, between Ferryside and Kidwelly.
It sleeps six, which is done with two bedrooms downstairs and one bathroom. It's got a 4 Star rating. It's comfortable and well done up, with the original stone walls and beams. There's a woodburner for cooler evenings. The garden is enclosed, so it's safe for kids and dogs. You can bring two pets.
Facilities are all there: WiFi, TV, washing machine. Bedding and towels are included. There's a highchair and a cot if you need them. Parking is on site.
You're a few minutes in the car from the local pub and restaurant. The beach at Ferryside is close. For a bigger beach, Pembrey is about a fifteen minute drive. It's really good, long sands. Kidwelly Castle is just up the road, which is worth a look.
If you want to explore, Carmarthen town is a short drive for shops. Laugharne, where Dylan Thomas lived, is about twenty minutes away. The National Botanic Garden of Wales and Aberglasney are both within half an hour. For a day out, the Gower Peninsula or Pembrokeshire coast are an hour or so's drive. They're very good for walking and beaches.
Useful links if you're planning: Visit Wales for general ideas, and Cadw for historic sites like the castles.