For a Run 'n Gun Light Armor spec I would suggest the following perks:
Run 'n Gun (increased accuracy with 1-handed weapons while moving)
Light Touch
Travel Light
Hand Loader
Toughness (x2)
depending on his chose weapons, one of:
Cowboy
Grunt
The Professional (note: only applies to sneak-crits)
with possibly one or more of the following:
Shotgun Surgeon
And Stay Back
Heavyweight
Weapon Handling
if in hardcoe mode and/or using heavy weapons:
Pack Rat (needs 70 Barter)
Strong Back