As a little help for the start to get into RP, some of the most common RP hubs I have knowledge of:
- Stormwind City (A)
- Lakeshire (A)
- Darkshore (A)
- Feathermoon Stronghold (A)
- Astranaar (A)
- Booty Bay (Neutral)
- Orgrimmar, Valley of Honor
- Silvermoon City
- A mobile hub initiative by Rogmasha ([H(/N?)-RP] A Roaming Hub - Session Three - Durotar's Heat! 🏜️)
That’s as many as come to mind for me at the moment. Even without an RP guild you should find RP in most of these places in the evenings.