Re above - Dalston maybe a good bet - my nephew used to live there and said it was rough but ok. I go there every couple of months from the sticks because it has imo best music venue in London - Cafe Oto - wild mix of free jazz/experimental/out musics, including a lot of 'folk' related stuff from performers pushing boundaries. I know the area from hanging about before gigs and general wandering and seems ok, with the market next door as well, but I'm used to cities so don't get paranoia, just step wisely. Good bus service round the clock. Used to live in London back when and if I was returning, this is probably where I'd look for somewhere relatively 'cheap.' Big city, big city prices but always deals to be had - flatshare seems best for initial step, I would have thought. Vortex jazz club as well, but Oto has a great vibe and refreshing to see such a mixed audience re age - from young to old.