To me it looks very much like a juvenile Ptyas mucosa. It was almost ready for shedding its skin. you can see that from the milky eyes and body.
It's a harmless snake, no need to worry about it. It does people (who don't like little rodents) a favor by eating rats and mice. This species can get quite long. I've seen them in the East of the country
The skin is a bit harder to tell. I would guess either cobra or one of the rat snake species like the one pictured.
Try to find the head, if it is still connected to the skin and post a picture. Or possibly look at coloration on the ventral scales (belly). Closer to the head cobras have a darker band(s) on the belly (google some images for cobras with the hood up showing their belly.). This banding should be slightly visible on the shed skin.
Also if there is a head, look for the skin covering the eyes. Rat snakes have rather large eyes compared to cobras. Also the large head plates are different between rat snakes and cobras.
One more thing, Mistifarang. I had a quick look on the link you added and clicked 'serpents' and found a few more snakes.
The python you have photographed is in fact a Reticulated Python, not a Burmese python. A quick check on google images will show you the difference between the two species.
And the third picture in the Flying Snake gallery is another juvenile rat snake. I think it is a juvenile Indo-chinese Rat Snake (Ptyas korros).
Concerning your answer nr. 1, would you be so kind to look at this one also? Can you please confirm that it's the Ptyas korros?
Concerning the skin I can imagine. I guessed only because of the Ptyas was around and I don't think the Cobra and/or the Reticulated Python I have seen here
were living nearby, although I had the Cobra in the house and the Python, Ptyas and flying tree snake around of which the flying tree snake is living here around the house somewhere.
My location is the Northern suburbs of Bangkok; I have seen the Python however already at the entrance of On Nut BTS and in thanon Koobon!