I don't remember the exact menu I chose, but it was easy back then. A few weeks ago. I'm not a freelancer tho, I mean, I work for a company, and in the company name I wrote like ㅇㅇㅇ News Agency from Korea. It was accepted.
I didn't get it well. You mention 14 days for Thailand? So, do you need a VOA? Where's your passport from? You shouldn't get a VOA is a DTV is being processed, as you can't have to active valid visa.
For short distance portions you can book only the day before. For example, in the train from Bangkok to Surat Thani, you can book Bangkok-Chumphon on advance, but Bangkok-Hua Hin only the day before. I know many people going to Hua Hin that book to Chumphon just to grab a seat. The difference in money wouldn't be much. I personally just book exactly at midnight, so there's always places.