I rode from Mexico to Winnipeg back in 2009. I rode through Fargo on my way north.
To reverse my route, get to PR-100 & MB-200 and head south. Do not take 75 as it is pretty busy and has no paved shoulder. There is a CS in St. Adolphe. At junction of 200 & 305 (near St. Agathe, restaurant), continue south on 200 (begin 8.5 miles of decent gravel) all the way to border crossing just west of Emerson. Dominion City has a grocery store, Emerson has a restaurant.
Cross border, ride on I-29 (great wide shoulder, legal, low traffic, and it is the only way) to Pembina, ND (very large CS). Go east on ND-59 which becomes MN-171. Bridge with HUGE tire grabbing expansion joints at border. Be careful!
Take MN-171 to US-75 and turn south. Hallock has a GS, R, CS, nice city CG. Due to a massive tailwind, I rode from Hallock to Winnipeg in one day, a Sunday. There may be more stuff open on other days, but a lot of places seemed closed on Sunday. I couldn’t tell if this was a Sunday only thing or a permanent thing since some towns (especially in Canada) had a store out of a non-descript metal building. I did not notice any legal CGs north of Hallock until Winnipeg. I would definitely carry at least an emergency ration or two just in case everything is closed.
Kennedy has a CS. Stephen has a GS that accuses you of stealing their money bags. http://www.crazyguyonabike.com/forum/board/message/?o=A&message_id=165384&v=1H
Argyle has a CS. Warren has a CS, R, GS, & CG.
Head west on MN-1 to Alvarado (tiny gas station with very limited stale products) and head south on MN-220 into East Forks, MN services and a GREAT CG). Cross river into ND on a bike path accessed on east side at Demers Ave & river. When you get to Washington Ave., turn south onto Washington which merges with CR-17 and CR-81. Thompson (off route) has a CS and allows I think allows camping if you call the sheriff. Reynolds (off route) has a restaurant I was told. Buxton has a small CS in the Cenex.
Hillsboro has a GS, CS, R, hotel, overpriced CG. Grandin has a CS & R on the west side of the interstate. I don’t think Gardner had any services (sorry, can’t remember). Argusville has a bar/restaurant but is not that good. Harwood didn’t seem to have any services.
Take CR-20/40th Ave. north of Fargo to the east to University Drive and turn south to 12th Ave. in Fargo.
One strong word of caution is that the wind is really strong out there. I had either great tailwinds or horrible headwinds. My mileage would go from 35-40 one day and be exhausted to over a hundred miles and had extra energy.