The Grooms Cottage is in Bishop's Castle, up near the top of the town. It's a one-bedroom place, sleeps two. It's got a 3 Star rating, so it's comfortable and clean but not luxurious.
It's attached to the main house, but you get your own entrance and the garden to yourselves. The garden has a gate that opens directly into the beer garden of the local pub. You really can just step through.
The king-size bed is in the eaves, so mind your head in places. The bathroom has a walk-in shower. There's a TV, WiFi, parking for one car, and bedding and towels are included. No pets, I'm afraid.
Bishop's Castle itself is small but has what you need: a couple of small supermarkets, a good butcher, a few pubs that do food, and some cafes. It's a good base for walking straight from the door. Offa's Dyke Path isn't far.
You can drive to Clun or Montgomery in about 20 minutes. Ludlow is about half an hour away, good for markets and food. The Shropshire Hills are all around you for longer walks or drives.
If you're coming with more people, the cottage next door sleeps four and you can book both together.
Useful links: National Trust Shropshire and Forestry England - Long Mynd.