Yeah, you've got to really stay in a stand off mode using reverse slopes and foliage on this one. It took me A LOT of tries, but once I realized this mission is all about scouting, airpower and precision artillery, it kinda all clicked. Gotta time your big airstrikes for the initial thrust of the mech divison zerg, that'll clog up the roads and create a lot of awkward movement that'll allow your troops to pick them off and then quickly withdraw. Rinse and repeat. I set up a small team in the left hand woods at the highest point (can snipe the harder to get AA from here), and the hill on the right is where most of the javelines / atgm should be concentrated in places easy to get reverse slope / foliage concealment from... GL!
Oh and I bomb the crap out of the village with one of the arties at least for a bit - the shell holes and carnage there also seems to cause some chaos when the zerglings try to rush through.