Choreography can be frustrating but can also be quite rewarding when the AI cooperates, having given it a bit of assistance.
Discovery (well, suspected and confirmed upon testing): Tanks will balk at rolling over known mines and, if there is no alternative route around them (due to, say, dense forest abutting the road), will sit and vegetate.
Adjustment: Provide a path of difficulty but still possible with effort. Set up a detour around each mine by widening the road a bit in selected hexes so that destroying a foxhole in the way is necessary to open up the path. An effective slow-down tactic to give the Finns a chance.
Here's the before and after. The AI, thank goodness, was smart enough to figure it out (look closely at "before" to see if you can trace the path for yourself):

- Screenshot 2.jpg (588.21 KiB) Viewed 2313 times

- Screenshot 1.jpg (557.59 KiB) Viewed 2313 times