3 or 4 days after Edinburgh

Will you have spent time in Edinburgh already?

If you do decide on Keswick, Manchester might be a departure airport as well depending on where you are flying to.

We will have spent ample time in Edinburgh. Great suggestion on Manchester. I think it’s a little closer by train to Keswick than Edinburgh and my connections home are basically the same. Do you need a car in Keswick?

If you are inclined, not far from Keswick is HillTop farm, where Beatrix Potter write her famous Peter the Rabbit stories. HillTopFarm link Docents give a tour of the house, tell some of the history.
. . . NOT to be confused with a crowded touristy place a few miles from there near Windermere, IIRC.

Closer to Keswick is the Castlerigg Stone Circle, again....if you're into that type thing. We are and enjoyed it. Called it a mini-Stonehenge without the throngs of people.
Link to Castlerigg

Great! Thanks. Any suggestions on where to stay and eat are appreciated as well.

We stayed at a Parkfield House B&B/Guest House while in Keswick, near the town center. We found the center to be rather small. We walked everywhere, including most of the way around the lake. We took the water taxi service from the far side of the lake back to town.

If you have a car in Keswick you could drive down to Grasmere to taste some of its famous gingerbread (Grasmere gingerbread shop). When finished, head to Cartmel, supposed birthplace of sticky toffee pudding (cartmel village shop).

Edited: If you have a car, it gives you more flexibility to get to small towns or sights. Since I always have a car in the UK, I can’t speak to public transportation or how well it serves the Lake District.

I should have been more specific about transportation. Do I need a car to get around the Lakes District in total, not just Keswick. It looks like the bus system is good.

We really liked the Grasmere Hotel in Grasmere. We had a lovely spacious room overlooking the large garden and the restaurant had excellent food.

We have always had a car when we visit the Lakes District. I think you would waste a lot of time if you were relying on public transportation.

One of the highlights of that area is Castlerigg Stone Circle.

Keswick doesn’t have a train station – nearest is Penrith then bus to Keswick.

You can see a lot of the Lake District by public transport

https://www.golakes.co.uk/travel/by-bus.aspx

If you hire a car you might as well hire at Edinburgh and drop off at Manchester if you're flying home from there. Parking in the Lake District can be a challenge.

Another couple places you could visit if you have a rental car are the Jedburgh Abbey and Melrose Abbey ruins south of Edinburgh. They are close to each other and kind of en route to Keswick. The town of Peebles is cute and in the area of Scotland where there are a number of woolen mills.

That’s great!! Thanks.