Oakwood Venbridge Farm is near Cheriton Bishop. It's a detached bungalow, so everything's on one level. That's handy if you don't want stairs.
It sleeps four in two bedrooms. One bathroom, which is a wet room with a walk-in shower. It's got a 4 Star rating, so it's well kept and comfortable.
The bit I like is the setting. You're right on the edge of Dartmoor, about a mile from the park boundary. The views are just fields and sky. You can fish in the farm pond on site, which is included.
Cheriton Bishop is a mile away. There's a shop and a pub that does food. The pub is decent.
For getting out, you're in a good spot. You can walk straight onto Dartmoor paths from here. Castle Drogo is close, and the Teign Gorge is good for a woody walk. The Dartmoor National Park site has all the route maps. Exeter is about eight miles east if you need a city or the train station.
Inside, it's open plan. There's a washing machine, WiFi, and a TV. Bedding and towels are included. There's a cot and a highchair if you need them. Parking is right outside.
You can bring one dog. The garden is enclosed, but it's not fortress-level, so you'd need to keep an eye on a real escape artist.