I edited it I accidentally pressed reply twice
Gotcha. Makes more sense now, I suppose, although I found that even when the levelcap was 30, I was far more in need of Perks than skillpoints. I believe I maxed out Guns, Sneak, Speech, Science, Repair, Lockpick, and Medicine, and I was damn close to maxing Melee and Explosives. Then again, I was playing with 8 Intelligence. Your mileage may vary.
Again, though...I can't really offer any better advice than I already have. I think your build is awful. That's certainly not a judgment on you or your abilities--if you can make it work for you, fantastic. But it does mean that the recommendations I can make are fairly limited and generic.
Anyhoo, having just double-checked, I'm going to retract my suggestion of the Hunting Shotgun, as it isn't affected by Cowboy, and instead suggest the Brush Gun--
IF and only if you level up before heading to the Big Empty and take the Hand Loader perk. .45-70 Gov't ammo is incredibly rare in and of itself, but with the ability to make hand loaded ammo, it becomes much easier to keep a good supply for the Brush Gun around. (Note that due to the nature of .45-70 SWC rounds, you may wish to also take Jury Rigging if you're able, as using .45-70 SWC ammo consistently will very quickly break your gun.) The All-American, a lightweight and effective gun chambered in a very common round and with the added advantage of a scope for distance shooting, is a good choice as a secondary weapon, while Pulse Grenades or the Pulse Gun should come with you to deal with the inevitable robots. Other than that--as I said, you'll want WMKs aplenty (
especially if you take Hand Loader and use .45-70 SWC rounds, and double especially if you do so without taking Jury Rigging), chems, and an assortment of skill magazines. Going by just what you said about having low Perception, I'd obviously recommend EW and Lockpick-boosting ones, but Science and Speech boosters probably won't hurt in this particular DLC.
Finally, if you have Honest Hearts available, Joshua Graham's armor comes in at only 8 pounds and offers 15 DT in addition to +3% Crit chance, which is a very nice bang for your buck. Again, though, if you don't have Jury Rigging it'll probably be hard to repair.