The short answer: to quit porn, you'll have to quit some other stuff too, even if those things on their own are harmless.
When we're at the edge of relapsing we're in full blown "zombie mode" and have no control. We put ourselves into zombie mode by following certain patterns of behavior. It could be routines, it could be thoughts, it could just be the course of our day. The further back from zombie mode you are, the more control you have. How far back do you need to turn the clock to a point where you can say "I am in control, and I'm going to behave differently"? Maybe after a night out, you decide "no computer until the next day" and find another way to unwind. If that is too much, maybe you limit your nights out. Maybe there is something about the night out that is triggering... maybe seeing attractive women out and about makes you feel anxious and lonely, and you react by looking at different facebook and instagram profiles, and ultimately hit up the porn. The more you break down this chain reaction, the more solutions will reveal themselves.
It seems like you've already found a few answers, but it is worth pondering it as you move forward.
I like what you say about "aiming small". Many rebooters get overly ambitious with what they'll do with their non-porn time, and fail to realize that they just won't have the mental or emotional energy to sustain ambitious activities like learning an instrument or learning a language. I like the idea of easy reading... even if it means young adult fiction or a Calvin and Hobbes book. It will absorb you, but demand little of you.