I've left my trailer for extended periods at both Clutesi and at the Clutesi overflow (across on Beaver Creek road in the grass). I've never had a problem, but then again I have never left anything that even resembles value in the truck. Really isn't that much $$, $5 a night I think.
Driving a truck and trailer (no boat) for someone who does not drive gravel much, I would suggest two hours is lots (that is how long it took me from Bamfield to Port towing my boat last week). By water to the Nook is dependent upon speed, I usually bank on an easy 90 minutes to Bamfield at 25-30mph. Just remember, Nahmint blows up in the afternoon so you want to be through by 10 or 11 or wait until evening. I'm conservative so would rather not tempt fate and go through when it is hot outside and that wind blows up in the afternoon.
The Bamfield road is really good at the moment but is VERY dusty and leaves one heck of a mess on a boat!
Sorry, no clue about launching at the Nook, I alwasy run down.
Cheers
RBF