You lucky duck! Wish I were going, but I don’t like crowds and the Olympics will be a draw for sure!
To all the great ideas that everybody has already said,
I would add Bermondsy Market,Camden Market and Portobello Market if you like flea markets and hunting for treasures! The Museum of Garden History in Lambeth and the Chelsea Physic Garden, Twinings Tea Shop, the Churchill underground Bunker and War Rooms.
The first thing I would suggest, and it sounds so touristy but really helps to get your bearings in London would be to take a Big Red Double Decker Bus tour.The ticket is good for 24 hours allowing you to hop off & explore an area then hop back on and listen to more of the interesting tidbits that the guide has to offer!
Get familiar with riding the Tube, it’s easy peasy and gets you to areas that would take ages to walk to!
I have to say that I’ve never had a bad meal at any of the many Pret a Manger locations (even in NYC!) the food is fresh and sandwiches made all day. The prices are reasonable too. Grab it to go & enjoy in any one of the gorgeous parks that are free for the enjoying~
Takes loads of pix and then come back here and let us know your experiences!