Just walk, it’ll be much faster than the bus which has to deal with traffic and crowds. You can re-check bags in E with DL outside customs and then walk to A via the indoor Skybridge with moving walkways.

Once you recheck your bag at the transfer desk, take the elevator near the Hudson News to Level 4 which is the SkyBridge. From there it’s a quick 5 minute walk to A, all indoors with moving sidewalks.