I can't actually remember where I first stumbled upon it. I think it was maybe on reddit? I was already aligned with the censorship/seizure resistance mindset and was probably on a path to become a gold-bug before discovering it.

I initially started with just interfacing with bitcoind via the rpc apis and had built a binary options / futures market prototype with it. From there I think I used Jimmy Song's programming bitcoin as a reference for building and understanding bitcoin more deeply. I've also been through aantop's mastering bitcoin and mastering the lightning network books. I also participated in chaincode's lightning seminar and highly recommend the self-paced content should you have the time and motivation. I tend to learn best by having a project that I'm excited to build and using it to motivate me to learn what I need to in order to get the project done.

Hm, it sort of depends on why you are running a node. If it's just for you to be able to make lightning payments somewhat regularly then I don't think it's that difficult at the moment. You could get away with using a mobile wallet pretty easily in that scenario. If you are a merchant/business who needs to receive lots of payments then managing your inbound liquidity is probably an important challenge to tackle.

I don't really read that much other than bitcoin/programming books. I'm currently doing another read-through of Mastering the Lightning Network at the moment alongside the bolts to make sure I really understand everything. As for fiction, I'd recommend neal stephenson (cryptonomicon and snow crash?).