Powerline is a mixed bag in terms of performance and in particular stability. With appropriate adapters (about $175 a pair) you could use other existing wiring,

Powerline is a mixed bag in terms of performance and in particular stability. With appropriate adapters (about $175 a pair) you could use other existing wiring, such as a phone line (VDSL2) or coax (MoCA). The fact that these technologies are mostly applied by internet providers doesn't prevent you from creating your private DSL or cable network. Either alternative would work a lot better.