In general the Wandle Trail was quite well sign-posted. Not every bit can be cycled, which is a shame, but mostly its bike friendly. Some bits (such as in King George Park) even had dedicated cycle paths, which is great.
The initial section was quite urban, heading up the Causeway passing one of the Thames Tideway Tunnel sites, then the South Circular road must be crossed twice to get to the Southside shopping centre. When I kayaked down the Wandle a few years ago, the dark tunnel underneath was memorable - particularly when we turned our lights out!
On the other side of that there are the first of the many parks, namely King George Park, with goal posts for football games, children's playgrounds and swarms of dog owners doing their walkies.
The path is forced away from the river at Earlsfield, and then becomes a corridor of green squeezed between industrial parks and terraced houses, connecting parks, in particular Garratt Park and Wandle Park (the first of two of that name I'd encounter).
This section also goes through a tunnel that was part of the world's oldest railway lines, the Surrey Iron Railway, which was a horse-drawn plateway along the Wandle valley, from Croydon to Wandsworth, which was opened in 1802. Parts of the route are still in use for the tram network, which is pretty amazing.
Some of the industrialisation is still visible, such as the Merton Abbey Mills:
As well as the many, many water mills along the Wandle, there were factories, including those of William Morris, the famous Pre-Raphaelite textile designer, poet, artist, novelist, translator and socialist activist.
It was hard to visualise those times, as its so different now, with housing estates, roads, business parks and a huge Sainsbury's supermarket. However away from this bustle in places it felt a lot quieter, maybe even pre-industrialised:
Finally, for this segment of the walk, I arrived at the very pretty Morden Hall Park, manged by the National Trust. There was a wooden walkway through the wetlands and on the far side reached this fetching bridge: