This was fun! An early morning subway ride to a harbourside shopping center, getting lost in said shopping center and pushing and pulling on locked doors. Finally underway and a short pavement walk to a disused rail corridor. A nice level walk through the greenway, with a convenient lunch stop at an airconditioned mall, to the other side of the country. 1 full day, could be split up.
Links:
http://singaporekitty.blogspot.sg/2014/04/i-walked-across-singapore.html
School students walk across for charity
http://blog.toomanythoughts.org/2016/01/walking-rail-corridor.html