[contingencies]

Actually Thai only has roughly twice the number of characters that we have in Roman scripts - excepting tones (a real pain) it is possible to learn pretty quickly. Lao by contrast has less, but has a rather tricky plethora of vowel combinations for a myriad of hard to distinguish eww, ieww, ooh, iuooh type sounds. :) Cambodian has no tones and is my pick for the one to go for if you are keen on an easy starter.

Tangential tidbit: I sent a copy of The Cambodian System of Writing (http://pratyeka.org/csw/) to TPB's anakata while he was solitary confinement to help him stave off boredom. No idea if he ever read it, though his mother assures me it arrived.

[vorg]

Besides ก (0xe01), the rest of the Thai characters (in 0xe02-0xe59) are letters ขฃคฅฆงจฉชซฌญฎฏฐฑฒณดตถทธนบปผฝพฟภมยรฤลฦวศษสหฬอฮฯะาๅ, alphabetic non-spacing marks ัิีึืฺุูํ which can follow the preceding characters, and render as stacked (as shown by the OP), five "marks" เแโใไ (with unicode's Logical Order Exception) which can precede the following character, diacritic non-spacing marks ็่้๊๋์๎ which also render as stacked, modifier letter ๆ ,digits 0-9 ๐๑๒๓๔๕๖๗๘๙ ,currency symbol Baht ฿, and punctuation symbols ๏๚๛

Thai looks to be a pretty gr๏๏vy language, like many other natural languages - perhaps some programming languages will catch up in their enhanced use of lexical tokens one day, instead of just relying on grammar, long English names packed into name hierarchies, and multi-ASCII symbols.

[boshea]

I think I would steer new learners of SE Asian scripts away from Cambodian as a first language to learn. Cambodian, while it is a beautiful script and has more-or-less regular pronunciation, also has a few odd exceptions, and complex vowel pronunciation rules. The consonants are divided into two groups, and many of the vowels are pronounced differently in the first group than in the second. That said, after learning the Thai script, Lao and Cambodian were not too hard. Either way, they are all great languages to learn.

[contingencies]

Actually I am almost certain Thai and Lao have those consonant divisions as well, in fact I believe 3 or 4. If I am not mistaken they are still taught and are part of the tone system and/or can affect unwritten vowel selection. More certainly, the consonant classes somehow stem from the need to preserve pronunciation of Pali, a middle-Indian prakrit language (with features not present in these SEA countries' modern languages) that is used as the littoral language of Theravadin ("older school") Buddhism. See http://pali.pratyeka.org/ for more info on that.