London's 2012 organisers have just 100 days to prepare for the biggest logistical peacetime exercise Britain has seen. Not to mention the arrival of 10,500 athletes, 21,000 media people and 8.8 million ticket-holders.

The gleaming nature of the permanent venues, from the stunning velodrome to the controversial stadium, has obscured the fact that some temporary venues are still to be built. The £35m "overlay" exercise, involving the installation of 200,000 temporary seats and 10,000 portable toilets, must combine perfect timing with heavy lifting. In Horse Guards Parade, home of the beach volleyball, 3,000 tonnes of sand need to be dumped and 15,000 temporary seats erected. In Greenwich Park, site of equestrian events, a huge area of land has been cordoned off for construction work.

Visitors to the test events have marvelled at the space age structures but were surprised at the expanses of concrete and lack of greenery. With huge temporary structures still being constructed, the Olympic Park retains the air of a building site and landscaping will be necessarily last minute.

There have been concerns over ticketing, the involvement of certain sponsors and the promised legacy. The debate over the budget, a huge hike in the security bill and what should be contained within the £9.3bn public funding envelope will go on. But, aided by the Olympic Delivery Authority building the permanent venues on time and on budget, Locog, the organising committee for the Games, has steered a steady course.

But the British public is not yet frothing with excitement. Nor are Londoners paying much attention to entreaties to plan their travel during the Games in order to avoid horrific congestion at key "hot spots".

The torch relay will help, as regional media promote the stories behind the torchbearers, but some may find the involvement of sponsors and its stage-managed nature too cloying. The London 2012 festival – the populist arm of the Cultural Olympiad programme – will also play a role.