Wimbledon to Windsor (and back)

Thanks in a large part to the built-in GPS of my shinynew iPhone, I made it to Windsor and back this weekend. All very flat and a fairly pleasant ride (although Feltham is a resolutely depressing place). 50.3 miles in total, done at an average speed of 14.7mph(apparently). So, next Saturday is going to be 8 hours, at the very least, of solid cycling - plus stops... Joy(!)...