Don't use fist-fighters? Fine, then solo this quest with a Small Guns tank!
A Small Guns Build
5.9.10.1.2.10.3, Small Frame + Bonehead
Tag: Small Guns, Lockpick (or First Aid), and Outdoorsman
Adrenaline Rush, Quick Pockets (for fast reloads), Even Tougher
Lifegiver, Action Boy, Bonus Rate of Fire,
Lifegiver, Action Boy (or last two of your choice, maybe Man of Steel and Toughness)
I took Quick Pockets so i can use the HPFA, and that's why i say "Reload" so much in this post. 762 ammo is great, so 1-hex with HPFA will bring down mutants the first time. But use Pancor Jackhammer too! It does some knock-backs from range and apparently the bursts don't spread.
Gear Up
Use combat armor/helmet, but watch deterioration level. Avoid all gear nearing 50%. Under 50% you get some bad troubles. 2000 rounds of ammo is plenty. Bring a backup gun and small amount AP ammo for it. Bring some ding-dang sstims! About 15. If you have 150 sstims, still don't bring more than 15. This will force yourself to be careful. If you bring too many sstims, you will skate through this quest without learning much - try to use less sstims each time you do this, and it will serve as some practice.
Approach
Take the same route as posted above to get a strong start. Use the back entrance and 1-hex those 2 back there. Easy. Get that door open however you have to, rAP (recharge AP) and run straight left to the laser rifle mutant. 1-hex him before he gets a shot, and stop. Reload and rAP. Wait for flamer mutant to close in, and 1-hex him too. Maybe he burned you a bit. Reload, FA, rAP and run outside the front entrance. Waste no time here - run straight at the visible target, 1-hex him, Reload and stop to rAP. LSW mutant will shoot at you - he uses his AP. That's when you 1-hex him and you made that look easy too.
Middle Guys
Upset them with a burst from range. They will start after you. You can weaken them a bit as they walk, but if you use HPFA then its really the 1-hex you want. Just remember: let the enemy get a shot off first, then you run up to 1-hex. If you run up to 1-hex when enemy has enough AP recharged, then you're the one who gets 1-hexed!
Use the corners near the entrance to wait for targets to appear 1 at a time, 1-hex and move away quickly each time. FA, Reload, rAP and repeat. (Use sstims only when you have to.)
Top Guys
Once things calm down in the middle, and you're back to full strength, run up left hallway and right up to the laser rifle, 1-hex him as fast as you can and he dies. His buddy will shoot you. Run back the way you came and keep going south because other targets will be after you from the far right. Get to a safe moment, Reload, heal up, rAP and hide around a corner by the shelves just inside to right of gate. You should get another 1-hex here but likely need to back off again and let the others chase.
Repeat tactics to reach last room with lockers. Remember to let the enemy get a first burst if they are already upset, and that's when you run up to do 1-hex.
Back Room with Loot
This is where the big boss is, with Avenger. He has 1 or 2 guards in there with him and one has a rocket launcher. Without Stonewall perk (you'd need ST 6), that RL guy will knock you down a few times if you don't hex him around a corner. The boss alone is no biggie though - you can fight him at range trading bursts back and forth a few times, using sstims to avoid failure.
The Prizes!
Yep you get a few fun items here, sometimes really good stuff, not to mention a Gatling Laser and Avenger. Items in lockers often have bonus stats. The main quest item is a trapped, metal briefcase with some blueprints in a somewhat-hidden crate in the top left room. Leave the box in tact to turn it in at GR, get 4k xp and be able to repeat this quest later. I hope you brought some expanded lock-picks to open that tough door (or some dynamite).