Updating the guide...
Altruist Acolyte isn't missable, really. There's actually more than 6 random encounters in which you can bring a stranger up there...AND, the game automatically tells you that you should bring them there the very first time a stranger gets into your car. I've even added a picture of the perfect time to get this done.
EDIT: Further updating....not going to list Wanted: Alive or Alive as missable either...as there are 5+ opportunities in which you can get this, and the VERY first one is not only detailed here, but it appears on your map as soon as Trevor is playable so there's no missing the mission.
Thanks to Xerofox for the rambunctiously romantic signature.
Last edited by BiggD; 09-21-2013 at 04:47 AM.