@Nick ******
you need to park yourself in a country long enough to get the DTV application thru the eVisa system at a consulate in that and get it approved. So about 5 working days from the date you apply
BOTH consulates in Lao are "walk up" consulates <- meaning you apply in person, not via the eVisa online system BUT you need to book an appt at those consulates to get IN the gate to apply and they both have 3 working day processing (apply one day pick up the passport 2 working days later.
BOTH consulates in Vietnam have eVisa system and you apply online depending on where you are staying IN vietnam <- they post they can have 5 business days processing
SO
if you want a DTV to thailand you're gonna have to put your round the world trip on hold and stay IN a country long enough to apply for the DTV wait for the processing, get the visa approved THEN you can go your merry way