Directions from Fargo to Williston are easy,
- drive east 300 miles from Fargo to Belfield
- stop for gas and a snack
- turn right -- drive 150 miles north to Williston
- replace windshield
- Delta, starting at $500 roundtrip, one-stop
- United, starting at $850 roundtrip, one-stop
- multiple other choices starting at $915 roundtrip, one-stop
See first comment. I completely forgot about Amtrak: $57 one-way this time of the year according to Amtrak's web page.
See third comment. I also forgot about Jefferson bus lines: $53 daily, one-way, according to website.