Chaucer's Nook is in Keswick, right in the middle of town. It's on the lower ground floor of a big house that was converted into apartments. It sleeps two people, one bedroom, one bathroom. It's got a 5 Star rating, which means it's done up nicely.
The flat is quiet, but you can walk to the Market Square in about five minutes. The lake is about ten minutes on foot. You can easily leave the car parked up if you want. There's a space for it on site.
Inside, it's all been done with good stuff. It's got everything you'd need: dishwasher, washing machine, WiFi, TV. Bedding and towels are included. There's a cot if you need one. No pets, sorry.
For walks, you can start right from the door into the fells. Keswick itself has all the shops and places to eat you'd need. Derwentwater is the lake here. A bit further out, you've got places like Borrowdale and Buttermere within half an hour's drive.
Useful links: Keswick Official Site and Lake District National Park.