One of my favourite riverside markets is Khlong Lat Mayom Floating Market in Taling Chan district of Bangkok. I went there the other weekend and it was just as popular as ever. If you are worried about crowds, I would strongly advise you to arrive by 9:00am at the latest. This is a great place to come to eat a meal or two and do some shopping. We also did a boat tour from here which lasted about one hour. You can take the public boat, but we decided to rent the whole boat for only 300 baht. I highly recommend doing this trip. If you don’t have your own transport, then just take a taxi. As long as you don’t come back too late in the afternoon, you won’t have difficulty in finding a passing taxi to take you back home.