>work a normal job
>slowly accumulate non perishables, rice, beans, nuts etc
>find a good spot near a river
>dig a large hole
>camouflage the hole and bury your food in the hole
>learn to fish, learn to use a gillnet
>learn your environment, what plants are edible, what is winter like etc
>slowly set up your base camp for long term survival, you could even buy a solar panel
>when ready, simply walk away from your life
It's that easy. That's how you leave society. That's how you 'run away'. It takes time. The more food you can store the better chance you have, if done slowly over time before you leave you could have 500+ lb of food stored and ready. If you're really serious you could withdraw money on a credit card and hold cash for if you run out of food but ideally you want to learn your environment and with a gillnet a big one you can catch more fish than you can eat.