Visiting Bangkok and wanting to try something other then Koh San Road? Then I highly recommend staying, or at the very least visiting in the Chinatown neighborhood of Bangkok.
You can spend hours wandering the tiny streets and alleyways of Chinatown, where you can find delicious bowls of noodles or other Thai dishes, for no more then 40-70 baht. Hundreds of street carts, markets, and stalls line the streets at lunch and dinner time. Not to mention the scene here is way more authentic then the one on Koh San Road.
Start at Yaowarat and Phadung Dao, walking along Yaowarat Rd headed west. Dip into a random alleyway, and start zigzagging. Make sure to remember a cross street so you don't get lost! At night, Yaowarat is jam packed with even more street carts and happy diners sitting at plastic tables set up just for the night.