4) Find and hire professional surveyor/captain. I'm assuming there will be an extra cost for the surveyor to act as captain for the sea trial...
Amending this one. Just spoke to two surveyors who basically said: no, it's the seller's responsibility to get the boat in and out of the boatyard where it will be hauled; he should pay for a captain if he can't/won't do this himself.
4) Find and hire professional surveyor.
4a) Tell seller to hire professional captain or otherwise arrange to get the boat to the boatyard and return it back after the survey.
4b) Coordinate schedules for a day that works for boatyard, surveyor, captain, and me.
At least one book I read suggested arranging stoppage points and consequentially a degree of discount with the surveyor if he finds something that's a clear deal-breaker for me (e.g. if he sounds the hull first and the core is wet beyond reasonable repair, why go further?), but I agree it seems unlikely anyone would risk losing part of a day's pay by agreeing to this. It also seems like it might bias an unscrupulous surveyor toward overlooking or not reporting such problems. Survey cost is nominal in the grand scheme of things, so, yeah, planning on just doing the full menu regardless.
So regarding sea trial, it sounds like surveyors aren't part of that process -- it's the owner or the broker (in the case of a brokerage listing) that takes the buyer out to test the boat's operating systems? Which means, per capta's post, I'll have to hire a captain to operate the boat (since owner can't) while I play with the strings and things?
I figured since many surveyors, including the two I contacted so far, also advertise their USCG credentials, delivery, and training services, they wouldn't hesitate to also move the boat and run the sea trial for additional fees. It would certainly make life simpler to have one person for the sea trial, delivery to yard, survey, and return delivery (assuming all can be done within an 8 hour day, which in this case should be no problem). But that does not appear to be an option.