Probably anyone who is involved in the "core" project will have to study Ethereum implementations. While the Ethereum Yellow Paper (https://ethereum.github.io/yellowpaper/paper.pdf) is probably the first source you want to look at, it doesn't cover specific implementation details such as how block reorganizations are handled. Unless you are already an expert in Rust or Go, Pyethereum is probably the easiest Ethereum codebase to study. Unfortunately it seems like Pyethapp isn't the most up to date implementation and for whatever reasons I wasn't able to immediately peer with other nodes.
The following is a workaround to import blocks from parity to get around peering issues.
- Install and run parity to sync up the needed number of blocks
- Export blocks from parity with $ ./target/release/parity export blocks ~/path/to/directory/chain.rlp
- Import blocks into pyethapp with $ pyethapp import ~/path/to/directory/chain.rlp
TODO: Explain how to extract block information