Character: The Mad Scientist
Evil Karma
Wear a lab coat glasses.
Use only energy weapons and plasma/EMP grenades. Use high endurance/agility so can withstand hits and dodge hits. High Intelligence of course for energy weapons + science.
Focus completely on energy weapons.
Play the game your way, decimating anyone you choose. Even full town's if you want. If I was this character, I would have definitely activated the bomb in megaton, and then slayed tenpenny towers too for my new home completely for myself. This character would be similiar to the scientist in FNV who is a human, who mistakenly thinks he is a ghoul and works as a scientist for the ghouls, except your Lone Wanderer version is obviously a lot more tough and dangerous, who doesn't work for ghouls unless it is in his best interests.
He can become like the Ant Antagonizer, except he is the mad scientist.
When the mad scientist finds a slaver camp, they know this is their last battle. His reputation knows no bounds in the wasteland.
You can also choose to make him good karma, who fights for the good of the wasteland. Like the lone wanderers dad in FO3. An inspirational character, if real life really was Fallout, that is who I would want my character to be like. "I heard about you de-activating that bomb in Megaton son, that was good."