You should be able to find enough Repair and Smoke Screen abilities to keep your units alive. I like to start with two APCs, convert one of the APCs to a Crawler, and then buy a second Crawler.
Be careful not to pick up any of the (many) Decoy abilities that get dropped onto the map. The achievement did not pop the first time I tried even though I did not use Decoy. It only popped the second time when I was careful not to walk over any of the Decoy icons that appear on the map.