It's called 1 Greta Side Court. It's a ground floor apartment in a building that used to be a pencil mill, right next to the River Greta in Keswick. You can hear the river from the balcony, which is a nice spot to sit out.
It sleeps four. Two bedrooms, one bathroom. It's got a 3 Star rating, so it's comfortable and clean. The building is on three floors, but you're on the ground floor so no stairs to worry about inside.
There's a shop and a pub about a hundred yards away, very handy. The views from the front look across Fitz Park towards Skiddaw.
You're right in Keswick, so you can walk to everything in the town. For getting out, you're close to Derwentwater. The walking routes from Keswick are endless. Cat Bells is a popular one, maybe a 15 minute drive to the start. If you want a proper mountain day, Skiddaw itself is right there.
For a drive out, Borrowdale is about ten minutes south, very pretty. Ullswater is maybe half an hour.
Facilities are straightforward: there's a TV, WiFi, parking on site. Bedding and towels are included. No pets, sorry. It can be decorated for Christmas if you book it over that period.
Useful links: Lake District National Park and National Trust Lake District.