Total trip cost, starting and ending at my front door and covering everything in between, was 11960 bt (~ $399). That covered 9 nights of lodging with A/C and hot water. Transport was 6 A/C bus rides and 1 with fans and open windows, an overnight train ride in second class and 2 days of motorcycle rental. About 3/4ths of meals were in restaurants, the rest from street vendors.
I knew Isaan was going to be inexpensive before I went, but had no idea that my per day average would be a little less than that of a typical month in Hua Hin. I’ve read the last five years have seen more expats moving to the larger towns in Isaan. In 2005 one received 75 Thai Baht for every British Pound. Today it’s around 49:1. That’s probably the biggest reason there are more expats in Isaan than before.