Aird Cottage is owned by my family. It's a big house by the sea just outside Dunure village, sleeps up to ten but you don't have to fill it. The views from most rooms are over the water towards Arran. The sunsets are genuinely very good.
It's got four bedrooms, three of them are kingsize. There are three bathrooms, one is an en-suite. Downstairs there's a kitchen, a living room, and a bathroom. The garden has a separate chalet. It has its own kitchenette, a kingsize bed, a sofa bed, and a walk-in shower. It's useful if some of your group want a bit of space.
The house is right on the Ayrshire Coastal Path. You can walk straight from the door. Turn left and you're into the Culzean Castle estate after a little while. Turn right and you can walk along to Maidens village. The path is good.
Dunure itself has a ruined castle and a decent pub. For shops, you'd drive to Girvan or Ayr. The big local attraction is Culzean Castle, about ten minutes by car. The grounds are massive and worth a full day. Turnberry golf course is a similar distance.
Further afield, Galloway Forest Park is about half an hour's drive. It's a huge area for walking. They have dark sky status if you're into stargazing. You can get boat trips from Girvan out to Ailsa Craig if the weather's right.
Facilities are what you'd hope for. Washing machine, dishwasher, woodburner, WiFi, bedding and towels are provided. There's parking for several cars on the gravel drive. The garden is enclosed. Sorry, no pets.
Useful links: National Trust for Scotland - Culzean and VisitScotland - Ayrshire & Arran.