i personally feel that send back to station buttons need to be added to the units as for me its the only thing thats stopping me from playing long games as it annoys me having to send the units back manually and having to make sure they are not blocking other vehicles from getting in or out apart from that the mod seems really good
Back to station commands may be coming in a future update but on the current map the only way is manually. If you right click + Shift whilst the lights are off on you vehicles your vehicle will move without activating light/sirens, and because the vehicles move slower its easier to get the units in to bays at the fire station. As Pottyscotty said has said in the past, if you get a large incident its probably better to restart the game after it.