My friend and I have been playing s lot. When they log out of my game for a short while, they are unable to log back in. If I close my game and re-launch it, then they can rejoin.
Since I don’t know how get a server or if it’s even possible, I leave the game running on my PC. I never get kicked out of the game and it is able to run for days. Unfortunately they are unable come and go freely.
They also get kicked out of my game if they idle for too long. We have tried making conveyor loops for them to ride while AFK, but no luck yet.