thai people can travel easily with no visas almost all over Asia , I live among very poor people , in C.M. almost everybody I know has a passport . I don't know about Buriram or Isaan
you're right roads can be slippery when wet ! also watch out for gravels , holes în the road , dead leaves , animal crossing , people driving on the wrong side , cars parked in curves .
When driving in Thailande be AWARE every second !!
Even if the pavement is in good condition! Almost everywhére in the North driving can be dangerous !