Chombueng marathon started way back in 1985 by a group of local health enthusiasts, and has strengthened its position as a grassroots event in the upcoming 35th edition. I took part in the 2016 edition. Chombueng is 130km from Bangkok, and is about a 2-hour drive towards the west. Registration for next year’s edition is already open. You’ll find lots of communication and instructions in Thai language, but that is part of the fun, indeed.