Leave enough horses around each pocket to keep it encircled, then with the rest snake for the victory points. If they're encircled they will try to attack and break out but this early they are super weak and your entrenched horses will be fine. The point of the this strategy is to encircle the US divisions and keep them in place, not actually killing them. Hopefully there will be a hole in their line and you can rush all your horses through. Once you're communist justify on the US and declare immediately. Then I built around 120 single battalion horses. I made about 12 10-width infantry and put them on a fallback line in the north (not counting the western penninsula) as a just in case measure. Go down the Communist path in the focus tree. The earlier you attack the US the better, since they won't have many divisions or military factories yet and there will be holes in their frontline. Go Communist and zerg rush the US with 1 battalion horse divisions, encircling the troops and rush the victory points.

Hearts of iron 4 communist