The first outpost
You can complete this mission very quickly by going to two individual spots: one to the West and one to the North. Outside of areas with houses and military installations, you do not have to worry that you will encounter any opponents.
Head North, to (M3,2). You can take out an opponent across the window at the upper floor. The other one should be patrolling the area at the ground floor. Eliminate the remaining ones, e.g. using stones to attract their attention. For this, perfect is the suppressed Walrod.
To clear the checkpoint, it is better to use sniper rifle, or a machinegun. Do not come to close to Jagers. There are two of them here. They are much more sensitive to your actions - their hearing and sight are better and their reaction is faster. It is best to wait for the most opportune moment to blow up the red boxes on the pile and the gas cylinder next to the gate. Finish off the remnants quickly.
Next to the control booth, there is a G43 (M3,6). This is a short range automatic weapon with high rate of fire. In this mission, you will not have much use for that.
The second outpost
Head towards the other outpost (M3,3) along the coast - there only are two opponents on the pier. You can easily take them down from a distance, or at close quarters. Shoot at the orange generator, approach the second opponent, shoot the first one and stab the other. In the box, there is M1911 (M3,7), which you will find not once and not twice again - unfortunately, this one is not suppressed.
Follow the coast until you get to the fence right by the checkpoint. Up ahead, there is a turret (M3,8) which turns every several seconds. After it turns towards you, note the small opening on the right - across the hole, you can kill the man operating it (you can, just as well, blow up the entire turret, but this will attract unwanted attention).
You can eliminate four of the opponents in a traditional way - using stones and pistol: allow one of them approach you while you are in the bushes, throw a stone ahead and, as soon as both of the opponents turn away, shoot the one standing further away and stab the closer one. Repeat this tactic in the case of the other pair.