I don't have an exact measurement, but I have a methodology that worked for me....
I measured
-- top of bow pulpit to water (while the boat was in the water)
-- added the designed draft (6'0 in my case, and because the boat was "light" when I measured that gave me a little buffer)
That should give you the worst-case height with the bow pulpit in place
Then, just to be sure that's the real worst-case
-- do the same measurement at the stern pulpit
-- then "sight" from bow pulpit to stern pulpit and see if there is anything (dorade guard, cabin-top winches) that sticks up higher than a straight line between bow-pulpit and stern pulpit.
Should be able to get a pretty good number - mine was within an inch.
If you need to pull the pulpits/stanchions off to make it work, I'd recommend doing the measurements above and then
-- calculate the difference in height between bow pulpit and stern pulpit measurements
-- tape a piece of lath to the stern pulpit and mark that distance on the wood.
-- run a taut string between the bow pulpit and the mark on the lath - you now have a "level line" you can use as a reference to see which things you'll have to remove. For example, if that string represents 15'0" total height, then you know that you'll need to remove anything that is within 1'-6" of the level of that string.
And, yes, you do want to get road-height to be less than 13'-6" The Federal standard is 16 feet (4.9m), but in urban areas the minimum clearance is 14 feet (4.3m). And the truck needs to account for the distance between ground and the bottom of your keel, hence the 13'-6" number. Taller objects can obviously be trucked over-road, but it limits the routes they can take and makes the trip more expensive.
$.02