You can rent a car with Hertz in Bangkok, They have 3 offices (both airports, domestic and intl.) and the central service station at Silom.
Book the "fun collection" for 4x4 Toyota.
You can return the car at Chiang Mai airport almost 8 years agoAnswered by Matthias Justin Case via WorldNomads.com
Hertz and Avis are very good in Thailand i use them often, if you rent a car use a brand name operator only. Remember by Thai law you must obviously have a normal license from your country PLUS an international drivers permit also. If you an accident it will be a big problem if you don't have both of these items. If you need a hotel on your trip check out this site it has good discounts on Thai hotels http://www.ihotelthai.com almost 8 years agoAnswered by Lani Jones via WorldNomads.com