Do this on a Saturday early on. Start at Waterloo or Westminster, and finish up at Borough market for lunch
I think they have live music on Thursday nights, and it's nuts. Try getting there early and grabbing a table in one of the nooks and crannies.
Brunch at the oyster bar but an amazing restaurant next door if you can get the reservations...
Go into the centre of the market - they tend to have live music around the place on Saturdays
