It's quite likely that the DLT office will require documents you don't have during your 10-day stay. That aside, the initial licence is only valid for two years, half of which you won't be here. Come for your holiday and worry about a licence when you move here.
He said he has a driver's licence and IDP. Why would it take so long? I walked into my DLT and out with my licence in less than 90 minutes. And most of that was sitting filling in time watching the Thai video while they processed it!