My character is making two journeys by car. One is from Whitechapel, London to somewhere unspecified in Cumbria (Keswick in Lake District works, it's in that area but even more out in the middle of nowhere) and back. The second is from King's Cross Station, where he's rented/hired a car, to the same place in Cumbria and back. He's interested in avoiding congestion charging on his way out of London, but not on the way back, since he'll be returning early in the morning in both cases.
So, what is the most obvious route for him to take? I'm most interested in the roads he takes to get out of London, since that's what I'll be describing the most. Also, how long would this trip usually take?
(If there's a more obvious place for him to rent a car in the second instance, feel free to suggest it, I just chose King's Cross because it's outside of the congestion area.)