A little time consuming, but not a very difficult mission. I completed it by myself today. Be aware that enemies will not always show up if they are under a lot of tree cover and you are scouting with the drone.
Objective 1 - Assist Allied Troops: It's helpful to have a grenadier here to take out the armored vehicle (3 grenades to kill, I believe) as you can't always rely on the A.I. Allied grenadier to do it. *Note: the more troops you keep alive here will help out with extraction later.
*After I completed this objective, I sniped the two rebels on the bridge, then went up the narrow path on the left and got a lot of enemies to funnel to me. With a group of players, this would be even easier, as some could circle way around to the left and flank.
Objective - Demo Railroad Car: Make sure this area is clear, then set your charge, get out of the way and watch the fireworks. *Note: I had the informant show up here once.
Objective - Gather Intel: This is at the northwest camp inside a garage. *Note: I saw 3 rebels in the garage with the intel. They won't show up on the drone. Clear the area and grab the intel.
Objective - Destroy the Tunnel: Once again, scout ahead, clear the area of patrols, set your charge and get out.
Secondary Objective - Neutralize the Informant: I've had him appear both at the west camp and at the windmill. Easy objective as all you have to do is shoot him.
Objective - Extract: This was really tense as I was by myself. Fortunately, I had kept a lot of the Allied troops alive at the beginning and they pretty much saved my butt here. When you get to within about 100 ft. of the extraction zone, you'll be notified that enemy reinforcements are on their way. They will be coming from both hills, left and right of the extraction zone. Work as a team and with the remaining Allied troops to take them out quickly.