Byre Cottage is a one bedroom cottage on the Olde Pensipple site near Trewidland. It sleeps four because there's a double sofa bed in the living room. It has a 3 Star rating. The facilities are basic but they work. There's a shower, a washing machine, WiFi and parking.
The cottage is converted from an old farm building. The ceiling has exposed beams, so if you're tall watch your head in a couple of spots. There's a patio area you share with the other cottages here, and access to the grounds which have a small lake.
You're in the countryside, about a fifteen minute drive from Liskeard. Liskeard has shops and supermarkets. The Looe Valley Line train runs from Liskeard to Looe, which is a nice way to get there without driving. Looe is a fishing port with a beach. The coast path is there if you want a walk.
Bodmin Moor is about twenty minutes north for walking. Siblyback Lake there has watersports. The Eden Project is roughly half an hour's drive if you're going towards St Austell. Fowey is a similar distance, that's a town on the estuary.
One well-behaved dog is allowed. Bedding and towels are provided. There's no mention of a cot, so if you need one you should ask.
Useful links for planning: National Trust Cornwall and Bodmin Moor.