If the Grand Palace is the heart and Thailand's Buddhist religion the soul then the life blood the main artery has to be without doubt the Chao Phraya River in Bangkok.
Bangkok is the Venice of the East !
Hop on and off the boat with an all day ticket , a quick and inexpensive way to see the sights.
The endless trains of barges being tugged steadily along the mighty Chao Phraya.
Wat Arun on the opposite bank
Some interesting sights along the river and well worth a day trip or better still a week because there is that much to see and do.
The long tail boats were about 800 baht for an hour.
The Hop on, hop off tourist boat was 200 baht a day.
Or you can travel like the locals on the river bus boats for 10 baht.