This is a tourist trap! Simple and easy as that. A big night market, nice and shiny, a boat ride will bring you here.
You will find some restaurants and many shopping possiblities. I personally find China town or Chatuchak market much more interesting. But if you are tired of the Thai jumble you will find here a European style shopping experience in a beautiful setting right next to the river.
The cache is at the telephone booth, look underneath!