Mouse Castle Barn is about a fifteen minute walk from Hay on Wye. It's a converted barn, one of two next to each other. You're on the edge of the town, so you get the quiet but you can still walk in for a book or a pint.
It sleeps six, in four bedrooms. There are three bathrooms, which is handy with that many people. It's got a 4 Star rating, which means it's well done and comfortable. The conversion is good, plenty of light and space.
You've got your own garden and patio area. Parking for two cars right outside. There's a washing machine, a dishwasher, and a cot and highchair if you need them. All the bedding and towels are included.
For walking, you're in a good spot. Offa's Dyke Path is right there. The official trail site has maps. The Black Mountains and the Brecon Beacons are a short drive. For a more organised day out, the National Trust in the Brecon Beacons has some great properties and walks.
Hay itself is about three quarters of a mile. There's a pub and a restaurant about the same distance in the other direction, towards Clyro. In Hay, you've got all the bookshops, a few supermarkets, and places to eat.
If you want to drive out, Hereford is about forty minutes. Brecon is maybe half an hour. The property listing says golf, fishing, and riding are nearby, but I'd check locally for the current details if you're keen on that.
No pets, I'm afraid.