ABSOLUTELY NOT!
Lay “tire blowout strips” to disable the trucks and busses.
Strategically locate the place to allow only turn arounds that head back south.
Military road checkpoints along the highway will turn around all vehicles. It cuts off their supply chain.
North is a permanent traffic jam.
South is open highway.
Walking North means starvation.
Walking South means buses to take you home.
Cut off the supply and redirect it.
Anybody still wanting to eat, heads back south.
Simple. - It is not rocket science.
I like one of your ideas in particular — take out their supply lines.
This is a heavily funded and organized effort. Seriously disrupt that organization. Hungry and thirty people will lose interest on marching. They will rape the land and nearby dwellings and cities scavenging, stealing and killing.
The mob will show its colors.