I loved staying at Primrose Place. It felt is like home away from home, but with the added bonus of a lovely little pool, a wonderful daily breakfast, weekly yoga classes, and two amazing owners (Somchoen and her daughter Primrose) who accommodate your schedule and needs and make you feel right at home. Their English is perfect, having lived some years in the US, which means they can really help you understand your surroundings better and feel more connected.
Rooms are clean, light-filled, and comfortable and have good AC. The grounds is beautiful and relaxing. The food is varied and delicious, and there are affordable laundry services on premises.
In addition, the place is just minutes away from the Mahidol University campus and the Mahidol International College in particular, which makes it great for international students visiting for both short and long stays. There are also many affordable and high end food options and restaurants around, a couple of beautiful and very convenient malls, the on-campus botanical gardens (some say they're the largest in Thailand), and many other attractions.
The place is about half an hour drive from central Bangkok, so take that into account. However if you're visiting Mahidol University (which has an excellent International Buddhist Studies program) or are looking for a home away from home around Salaya or Nakhon Pathom - this is the place for you!