24 is cold. If you are in the water, no biggie, but on land:
I would open my block drains and make sure that the passages aren't clogged with sand/mud/dirt. Other than that, I wouldn't think that you need to do the full winterization. If you have a power steering cooler loop I might unclamp on end and drain it out.
If you have fresh water, make sure that the lines are clear. Or, go ahead and add RTV if you use it.