Hi
Greyhound and Jefferson bus lines cut services to parts of ND over the past few years. Greyhound goes along I-94 and I-29 but not along Highway 2 which goes thru Towner. Jefferson bus lines goes up I-29 with service to the far eastern part of the state.
Your best bet might be on Amtrak....depending on where you are from. Amtrak as service along the northern route through Minot to Rugby to Devils Lake to Grand Forks and then onto Fargo...Minneapolis and Chicago. But you will still have to find transportation or a ride from a friendly stranger to Towner. I travel back and forth along Highway 2 often as we have relatives in Minot area and there is a big sign upon entering Tower claiming it to be the cattle capital of North Dakota. The area is flat prairie and McHenry county where Towner is is made up of small towns with Germans or Germans from Russia the main ancestry. There is a gas station/convenience store along Highway 2 with pizza, etc.... I havent ventured into "town" but most of these places have small downtowns with a few spots to shop/eat. No chain restaurants in the county no Walmart (yet) nor no McDonald's etc...
http://www.amtrak.com/pdf/national.pdf
Dan