Central Mahasarakham is walkable: the clock tower, the central market, the downtown MSU campus, and Wat Mahachai are all within a 15-minute walk of each other. For anything further — the Khamriang campus, Kaeng Loeng Chan, the long-distance bus station — songthaews (covered pickup trucks running fixed routes) and motorbike taxis are the local options.
Songthaews to Khamriang run from a stop near the clock tower roughly every 15 minutes during the day, with a fare of around 20 baht. Motorbike taxis cluster at the market and outside the university gates; agree the price (usually 40 to 80 baht for anything in town) before you climb on. Motorbike rental is cheap if you have the experience for it — 250 baht a day for a 110cc scooter is standard. There are no metered taxis. Bicycle rental is available from one or two small shops near the downtown campus and is a reasonable way to get to Kaeng Loeng Chan in the cool months.