Because post-apocalyptic adventure and sword and sorcery are so closely related as genres, the transition from one to the other should be fairly easy (and fun!). For example:
soldier
Some take up arms for glory, wealth, or revenge. Others do battle to prove themselves, to protect others, or because they know nothing else. Still others learn the ways of weaponcraft to hone their bodies in battle and prove their mettle in the forge of war. Lords of the battlefield, soldiers are a disparate lot, training with many weapons or just one, perfecting the making and uses of armor, learning the fighting techniques of exotic masters, and studying the art of combat, all to shape themselves into living weapons. Far more than mere thugs, these skilled warriors reveal the true deadliness of their weapons, turning hunks of metal into arms capable of taming kingdoms, slaughtering mutants, and rousing the hearts of whole tribes. Mercenaries, shock troops, hunters, and artists of war, soldiers are unparalleled champions, and woe to those who dare stand against them.
Role: soldiers excel at combat—defeating their enemies, controlling the flow of battle, and surviving such sorties themselves. While their specific weapons and methods grant them a wide variety of tactics, few can match soldiers for sheer battle prowess.
Alignment: Any.
Hit Die: d10.
Class Skills
The soldier's class skills are

Climb

(Str),

Craft

(Int),

Drive (Dex), Handle Animal

(Cha),

Intimidate

(Cha),

Knowledge

(ruins) (Int),

Knowledge

(engineering) (Int),

Profession

(Wis),

Ride

(Dex),Survival

(Wis), and

Swim

(Str).
Skill Ranks per Level: 4 +

Int

modifier.
Table: soldier (per fighter table)
Class Features
The following are class features of the soldier.
Weapon and Armor Proficiency: A soldier is proficient with all

simple

and

martial

weapons Archaic and Modern, and with all Modern and Archaic armor (heavy, light, medium and piecemeal) and all shields (including riot shields).
Bonus Feats: At 1st level, and at every even level thereafter, a soldier gains a bonus feat in addition to those gained from normal advancement (meaning that the soldier gains a feat at every level). These bonus feats must be selected from those listed as

combat feats, sometimes also called “soldier bonus feats.”
Upon reaching 4th level, and every four levels thereafter (8th, 12th, and so on), a soldier can choose to learn a new bonus feat in place of a bonus feat he has already learned. In effect, the soldier loses the bonus feat in exchange for the new one. The old feat cannot be one that was used as a prerequisite for another feat, prestige class, or other ability. A soldier can only change one feat at any given level and must choose whether or not to swap the feat at the time he gains a new bonus feat for the level.
Bravery

(Ex): Starting at 2nd level, a soldier gains a +1 bonus on Git Check

Will saves. This bonus increases by +1 for every four levels beyond 2nd.
Armor Training

(Ex): Starting at 3rd level, a soldier learns to be more maneuverable while wearing armor. Whenever he is wearing armor, he reduces the armor check penalty by 1 (to a minimum of 0) and increases the maximum

Dexterity

bonus allowed by his armor by 1. Every four levels thereafter (7th, 11th, and 15th), these bonuses increase by +1 each time, to a maximum –4 reduction of the armor check penalty and a +4 increase of the maximum

Dexterity

bonus allowed.
In addition, a soldier can also move at his normal speed while wearing medium armor. At 7th level, a soldier can move at his normal speed while wearing heavy armor.
In addition, when fashioning Piecemeal Armor, the Material Quality rating is automatically increased by one.
Weapon Training

(Ex): Starting at 5th level, a soldier can select one group of weapons, as noted below. Whenever he attacks with a weapon from this group, he gains a +1 bonus on attack and damage rolls.
Every four levels thereafter (9th, 13th, and 17th), a soldier becomes further trained in another group of weapons. He gains a +1 bonus on attack and damage rolls when using a weapon from this group. In addition, the bonuses granted by previous weapon groups increase by +1 each. For example, when a soldier reaches 9th level, he receives a +1 bonus on attack and damage rolls with one weapon group and a +2 bonus on attack and damage rolls with the weapon group selected at 5th level. Bonuses granted from overlapping groups do not stack. Take the highest bonus granted for a weapon if it resides in two or more groups.
A soldier also adds this bonus to any

combat maneuver checks

made with weapons from this group. This bonus also applies to the soldier's

Combat Maneuver Defense

when defending againstdisarm

and

sunder

attempts made against weapons from this group.
Weapon groups are defined as follows. Individual weapons within each group are listed in the Equipment chapter.
Melee, Slashing (ex: axe, broadsword, cleaver)
Melee, Piercing (ex: spear, rapier, knife)
Melee, Crushing (ex: hammer, mace, club, tire iron)
Melee, Powered (ex: cattle prod, chainsaw, vibro-blade)
Ranged, Thrown (ex: shuriken, shot put, grenade)
Ranged, Muscle Powered (ex: bow, sling, slingshot)
Ranged, Mechanical (ex: crossbow, manapult)
Firearms, Small Arms (ex: pistol, hunting rifle, nail gun)
Firearms, Automatic (ex: auto-pistol, assault rifle, needler)
Firearms, Heavy (ex: machine gun, grendade launcher, micro-turret)
Energy Weapons, Light (ex: laser pistol, plasma torch, destabilizer)
Energy Weapons, Automatic (ex: laster rifle, gravigun)
Energy Weapons, Heavy (ex: tesla coil, gravigun, imploder)
Natural Weapons, Melee
Natural Weapons, Ranged
Natural Weapons, Energy
Vehicle Mounted Weaponry
Computer Controlled Weaponry
WMDs
Armor Mastery

(Ex): At 19th level, a soldier gains

DR

5/— whenever he is wearing armor or using a shield.
Weapon Mastery

(Ex): At 20th level, a soldier chooses one weapon from a weapon group (as above) with which he has a +3 bonus or greater. Any attacks made with that weapon automatically confirm all critical threats and have their damage multiplier increased by 1 (×2 becomes ×3, for example). In addition, he cannot be disarmed while wielding a weapon of this type.
(quick and dirty mod of the fighter entry from the PFSRD)
EDIT: sorry about the smilies. How'd that happen?