There's a really good write up in the below link about how they intend to implement the single persistent galaxy. Only combat will be instanced, nothing else will be. Well worth a read to see how you'll connect to the game and hook up with your fellow dMw citizens!
https://robertsspaceindustries.com/comm-link/transmission/12770-Chris-Roberts-On-Multiplayer-Single-Player-And-Instancing