Can I leave Thailand by bus to a neighboring country for a visa run and return with a new 180-day stamp on my DTV visa?

You can leave Thailand by land (bus or other means) to a neighboring country and return without any issues. Many expats have successfully done border runs this way, receiving a new 180-day visa stamp upon re-entry. Make sure the border selected allows same-day return, and remember that different modes of transportation (car, train, motorbike) are also viable options for border runs. There is a general understanding in the community that both air and land exits are acceptable for visa purposes.