It even has a nice pool and few places beat their rates.
It is situated in Bangpli, Samut Prakan. 15 minute cab ride.
Make sure to print out the thai map on their homepage, before going, as few drivers are familiar with this general area let alone the place Sananwan Palace. Or arrange a pickup with the hotel.

You can easily kill a day or two in this general area by visiting the Erawan Museum, Muang Boran aka Ancient City and the Crocodile Farm.
There is a very nice restaurant on the river bank within walking distance from the Sananwan Palace, Moo Yim, the smiling Pig. Try out their Moo Kata, all you can eat 80 Baht. If you travel without your wife, make sure to order Tiger Beer. Those lassies serving Tiger Beer are pure eyecandy.

There is a local market too right on the river bank next to the temple Wat Bangpli Yai.