The Line Modern Art Walk (Stratford to North Greenwich) walk

7.7 km (walked) plus 3 stops on the DLR and the Emirates Air Line cable car over the Thames

This walk makes use of the The Line – London’s first dedicated modern and contemporary art walk, which is fully waymarked and split into three parts, which are linked by a short DLR ride and the Emirates Air Line cable car across the Thames. It has a changing range of – currently – about a dozen sculptures displayed, all by prominent artists.
The route initially follows the River Lea, passes Three Mills Green & Water Mill (the largest tidal mill in the world) and the Film and Television Studios (London's largest) and then – a little further along The Lea – Cody Dock, an interesting community project on a former Gasworks site. After a short ride on the DLR you walk along Royal Victoria Dock and take the cable car across the Thames.
The route then finishes with a stretch along the Thames Path rounding the O2-Dome, before turning to North Greenwich Underground Station and the neighbouring wide range of eateries and waterholes on the plaza and inside the Dome itself.

the-line.org - official website

You can cut the walk short at Star Lane DLR/Canning Town tube stations (4.5 km walked distance) or at North Greenwich tube station (before rounding the O2-Dome, 6.1 km walked distance).

Miller’s House Café in the House Mill, Three Mills Lane, staffed by volunteers, open 11.00-16.00 weekends and sometimes also on weekdays
Cody Dock Café on the River Princess, Cody Dock, 11c South Crescent
The Cabin Café, Cody Road, open 06.30-14.00 Mo-Fri
Several options around Royal Victoria Docks
Plenty of options in North Greenwich, in and around the O2-Dome