My neighbor introduced us to this hidden gem. And, in the case of Baan Rabiang Nam, I do mean hidden!
Located north of Bangkok, in Nontahburi, its distance from downtown isn't what makes it inaccessible. there is no parking and the small soi in doesn't lend itself to taxis. One has to park at nearby Wat Khae Nok and take their moto-shuttle into the restaurant.
Once found, one will find it worth the hunt. We have been a couple times now and have found the food to be as good as any, and better than most that we have found anywhere. We have yet to have a single dish disappoint.
The atmosphere is rustic and comfortable,; the service attentive, but not intrusive. Their menu is in Thai and English, with quite a few photos. You can pull their full menu from their website.
The easiest way to visit might be for lunch. You can catch a Chao Phraya express boat to the Nonthaburi pier, N-30. From there, most drivers should know the place. A dinner visit will require transportation to and from Bangkok. The express boats don't run at night.
I've included a few photos and a link. Besides a full menu, their site includes a map. It wouldn't be a bad idea to copy this for any driver you use.