I never played any complex PnP game. When I was like 13, I used to do PnP with a simple coin (usually a quarter), a piece of paper and pen. I wouldn't go as far to have stats and all that though. It would be simple. You have you inventory, hitpoints, damage (affected by what you have equipped), and that's it (except if your fighting someone, they have that also, which I would randomly make up instead of going by a handbook).
Then I would just make it up as I went along .For example, say I was doing a modern theme. "You come across a car, and you still have 500 miles to get to St. Louis. Steal It. (Yes). Then you would flip the coin, Heads: You successfully take the car. Tails: You fail the hotwire attempt. Say I landed on Tails. I try again. Heads: You hotwire the car with on second try, without problems. Tails: You hotwire the car, however a local highway cop saw you. Stop to talk to the cop or drive away in the car? Say you stop. The cop tries to arrest you. You can A) Let him arrest you, B) Attempt to bribe him for $1000, or C) Before he puts his handcuffs on you, attempt to make an escape, or D) Fight him. Then say you choose B, flip the coin and Heads: The bribe was successful, however you only have $200 dollars left, or Tails: The cop is dirty, and handcuffs you anyways after taking ALL of your money. Then I'd just carry on like that.
But that was 8 years ago lol. I'm not really into PnP anymore. Everytime I try I just end up getting bored with it.