Keswick in late Nov

Will you have a car? Bus schedules are reduced and the Beatrix Potter heritage sites (in other towns) are closed.

I can't judge late November too well except that the days are short and weather likely to be chilly in the Lake District (more so that some other parts of England). The town of Keswick struck me as awfully touristy, so in that sense late November might be advantageous. What are your interests? For example, do you want to go walking (hiking) in the hills, or are you more attracted to in-town pursuits?

The Lake District can actually be quite nice in late Nov. depending on how lucky or unlucky you are with the weather. If it's clear then it can be stunning! Blue skies with a dusting of snow on the fells is just spectacular. If it's freezing and raining though it won't be very much fun. Maybe you have the luxury of deciding at the last minute whether or not to go there basing your decision on the weather? B&Bs aren't solidly booked at this time of year so you could easily do this...
The bus schedules actually aren't reduced to a significant extent seasonally in the Lakes - the residents still need to get around! The only limited lines tend to be out to the more remote villages. If you only have 2 days then you most likely won't be going to any of these anyway.

To be able to answer your question fully, you ought to state what the alternative is. How far out of your way are you going to get there?

I have been to the Lakes in November and had several days of mist and rain when you can't see the fells (hills). Unless you are unlucky, snow is unlikely so early in the winter. At that time of year, rain is likely and the days will be short. The seasonal bus services won't be running, but there will be a basic bus service.

In summary, the Lakes in November without a car wouldn't be my first choice of destination.