I stumbled upon a workaround for this task where the Freedomers don't follow Max to the farmstead. I had to do a Quick Save outside the Freedom base while Max and I were in a low spot out of sight from the farmstead. When I reloaded the save, Max ran back toward the starting point (as many of the NPCs do). At the same time, the rest of the squad started moving toward the farmstead.
This gives you some support, but Max is frozen back at the base where he first instructed the raiders. Eventually, Max returns to his original spot and you can talk to him again.