A good summary of what to do.
I
always ask to take the highway. The 60 baht is money well spent.
I have never had any problems getting a taxi - perhaps with the exception of the day the new airport was opened. Things were a little chaotic that day ...
You forgot to
insist to the driver to turn on the meter ! (Unless you really know what you are doing and can haggle a lower price than the meter would produce)