Thanks everyone, for your comments. It's nice to know that others can feel the same things.
Your guests have never been on this type of vacation and will have great fun even if it’s unplanned locations and schedule. No need to worry. I’m guessing they’re generally not the complaining type or you wouldn’t have agreed to the trip.
Yeah, these guys are NOT the complaining type. We camp with them all the time and take other trips with them and have had many adventures along the way. I think the difference in this case is that I'm the expert. Nothing happens on this trip without me and everything hinges on me not screwing up. We have regaled them with the tales of our past trips (which got them excited to join us) and I became this all-knowing master seaman who can handle any situation. Now I have to put up or shut up. I can handle effing up in front of my wife. Losing face in front of my friends is another thing.
Don't get me wrong. I'm not losing sleep over this. It's really just a subtle feeling of a tiny bit of extra pressure - like it sounds like others have had. It does help to lay it out there though.
And alas, no, I can't turn this over to anyone's deity. Gotta man up and handle this myself.