I fish area 13- not a lot until late July/August these days...blackmouth's gotten pretty scratchy...
Coming from Shelton?
Nothing wrong with going up to Narrows to put in, but I don't see an advantage really, at least this time of year.
You could launch at Zittle's Marina which puts you very near Johnson Point and a short run from Devil's Head and Lyle Point at the s. end of Anderson Is. I would say those are the 3 most well known spots down there that might hold blackmouth. Granted it's not like I've heard of any good reports lately.
For Johnson Pt. I'd fish the west side on incoming, east side on outgoing. Devils Head and Lyle fish the down current side on either tide.
If you put in at Case Inlet, I'd fish for searun cutthroat- which could be decent bet for action btw.
Don't know bupkis about the Dabob option. Manchester seems like a looong boat ride to area 13...
Hope it helps you narrow down your choices.