Sandy's Hoose is in Portmahomack. It's just up from the beach, so the front rooms look right out over the sand and across the firth. You can see the hills in the distance.
It sleeps six, in three bedrooms. There are two bathrooms, which helps. You can bring one dog.
The house has been done up, but it's still an old house. It's warm, and it's got everything you'd need. There's a wood burner for the evenings. The kitchen has a dishwasher and the utility room has a washing machine.
You're basically on the beach. A two minute walk and you're there. The village has a shop, a pub, a restaurant. All the basics are covered.
If you want to go out, Tarbat Ness lighthouse is a good walk. The Tarbat Discovery Centre is here in the village if you're interested in the Pictish history. For a bigger day out, Dornoch is about twenty minutes north. Inverness is about forty-five minutes south.
Dunrobin Castle is worth the drive if you like that sort of thing. The ferry to Orkney goes from Scrabster, which is just over an hour away.
Facilities: All the bedding and towels are included. There's a cot, a highchair, and a stairgate if you need them. There's bike storage. There's a patio garden out the back. You can park on the drive.
Useful links for your planning: Walkhighlands for routes, and National Trust for Scotland.