I expect I will come here again. Though it would be best if you have something else planned for the rest of the day. It took me about 30 minutes to drive there from kanchanabiri. We drove on Highway 4 towards Nakhon Pathom. We turned right at Nakhon Chaisi and then left onto Highway 3223. The journey there is signposted in Thai and English. If you live further north in Bangkok you could try Highway 346. I have marked the location on Google Maps. I also suggest that you buy the map book “Bangkok & Vicinity: A to Z Atlas” published by PN Map as the floating market is marked. Your other options are to rent a taxi for the day for about 1,200 baht (it cost me 400 baht in petrol alone) or take a local bus from either Nakhon Pathom market to Lampaya or a mini bus from the Southern Bus Terminal near Kung Luang Restaurant.