The Wild Territory is a pretty large area consisting of large storage hangars, various buildings, railroads and abandoned train wagons. There's plenty of artifacts (including a very rare one) to be found and some pretty good secret stashes, if you can acquire the information about them; you'll also be able to find a unique pistol - the Big Ben.
If this is the first time you're in the Wild Territory be aware that there are four Merc snipers ahead all armed with scoped Akm 74/2 rifles. Move closer and take them out while using some of the construction materials as cover. There is another Merc below, wielding a TRs 301 (a great weapon, especially when fitted with a scope and possibly a grenade launcher and a silencer). Once you've dealt with the 5 Mercs here, be sure to loot them; you can also find a Stalker Suit at the end of the elevated area where the snipers are.
When you move on you'll intercept another message - there are more Mercs ahead (including a sniper in a tower to the north-west) so proceed with caution. This area likely has numerous artifacts scattered around, so before you head on make sure to do a proper search.
Moving on you may be interrupted be a short in-game cutscene showing you the area ahead, along with a transmission from Professor Kruglov - he, and a number of scientists, are pinned down by Mercs and could use some help. I say may because it depends on how you move on - if you move through the radiated building then you wont see the cutscene, but you'll still get the transmission eventually. I personally find that going through the radiated building is the best option since it will get you closer to the scientists, and it's easier for you to stop them from killing their main target, Kruglov. This way will require you to deal with some Mercs before you reach the scientists, but they shouldn't pose a major problem.
Keep focus on dealing with the Mercs and rescuing Kruglov - you can always search the area afterwards. Once you reach the scientists be sure to deal with any remaining Mercs - the mission wont be updated when they're all dead so you'll have to make sure yourself. Once the path is clear, go talk to Kruglov. Once you do you'll receive the Lead Kruglov to Yantar mission (if you decide to help him further, that is) and you now have to escort him to the entrance to Yantar. Two times on your way there, Kruglov will warn you about approaching Mercs; he'll stop and wont move until you've dealt with them. The first will come from behind you (from the north or north-east). Next he'll stop and there will be three mercs ahead of you, just around the corner. You'll finally come to a tunnel filled with Burner anomalies - Kruglov wishes you to go through first to make sure it's safe. Stay near the center and use bolts to get a clear fix on where the different anomalies are located. The tunnel is also filled with especially Droplets and Fireball artifacts so be sure to pick up as many as you can carry. Once you reach the other side of the tunnel Kruglov will start to move towards you - make sure you eliminate all the zombie stalkers that may be around so that Kruglov has a clear path.
When Kruglov has made it to the other side, talk to him and he'll give you his flash drive which you can deliver to the Barkeep who will give you 5000 RU for it. He also promises you a scientific suit (which translates to a SSP-99 Ecologist suit) when you visit them at the mobile lab. You can also ask him for some information about the area and the Zone. If asked about X16 he'll tell you to ask Professor Sakharov at the mobile lab in Yantar.
Now that you have saved Kruglov you may wish to backtrack and loot the Merc (and scientist) corpses, and check out the area for more artifacts. You can find a metal box next to the chopper - it contains some of the still rare 9x39 mm SP-5 rounds (used by Big Ben and the the Vintar BC rifle, for example). Next to the train track you can find a dead merc with a RPG-7u grenade launcher and one grenade. As I said on an earlier page, dragging this weapon along is probably just going to be a burden since you wont find any ammo for it, and it is quite a heavy weapon as well.
Just south of the chopper you can find an underground tunnel - this tunnel does not only contain the family rifle mission item but also a unique pistol, Big Ben, some 9x39 mm ammo, a Pellicle arfiact, and a dead stalker (who has Gordons PDA - a small tribute to the Half-Life series). Jump on the various objects - cars, containers, etc. to avoid the anomalies here. The family rifle is in fact just a regular Sawn-off Double-barrel and you can find it in a container behind the one with the metal box in it. Hunter at the Bar will give you 4000 RU in exchange for the family rifle, along with information about a stash inside a house in Wild Territory; the stash contains the excellent SEVA Suit so be sure to pick it up; refer to this page on how to reach the stash.
If you don't wish to head back to the Bar and drop off all the loot you've probably collected by now, there is a blue box stash at the mobile lab in Yantar that you can use - also, Sakharov functions as a trader so you can sell any equipment you dont need.