Your question is a little confusing; Not sure of what you mean by Thailand = worst humanities project?!?
And if you want a "full on holiday" for 6 days, $15,000, is that USD's? (480,000 baht) is more than enough, you can live like a queen spending 80,000 baht a day.
If you mean 15,000 baht for 6 days (2,500 baht a day), check out hotels on this site, there are a few in the 500-600 baht per day range.