Let the players control multiple characters, though only one per session.
Have a "Table of DOOM" that you roll on when NPCs go adventuring. Add things like "Gained confidence; believes he should be leader of the colony and will start plotting a rebelling", "Replaced by doppleganger assassin", "Pulled a sword out of a stone; by all rights he's the king now", "Possessed by demon", "Brainwashed by cult", "Found treasure, going to start his own competing colony", "Gone native", etc. If you want to send out NPCs to do your job for you, it might come around to bite you in the ass.