I agree that both Lightnin' Hopkins and Big Bill Broonzy are good "transition" artists from the old country to the newer urban blues.

I would also add Sonny Terry and Brownie McGhee. They played right through and beyond the folk boom of the 60s

They represent the lighter hearted Carolina-style blues. Sonny Terry (harmonica) was right in ther at the beginning, accompanying Blind Boy Fuller.

When Fuller died suddenly, Brownie McGhee inherited his National Resophonic and Sonny Terry. That, of course is an over simplification; but Terry does provide a bridge.

Both were friends of Leadbelly and even lived with him for a while. Terry recorded with him on the Folkways label

McGhee's father was also an old-time guitarist--I have read of the ragtime school.

And speaking of Leadbelly, he was a general songster and didn't stick to the blues; but he does a good job with them and tempered his style to be palatable to his urban white listeners of the 40s and 50s. He is worth listening to.

Murray