OK, this sound possible, just not...um..."advisable".
Roger, do you feel the satellite image on Google Maps is reasonably accurate? Not too old?
West Pass looks reasonable straightforward, assuming you take it during higher water.
South Pass looks "wicked, tricksy, false." [movie quote!]
Even so, the detail on Google Earth is pretty good; it's dated August 23, 2007. And Google Earth (the app, not the web-based map service) appears to allow realtime GPS plotting. I could imagine having Coastal Explorer and Google Earth running side-by side, both plotting the GPS data in realtime. I would need a navigator to watch that computer like a hawk, giving me constant feedback about our location relative to the channel, while I run the boat and watch the depthsounder like a hawk. One person can't do all three tasks, I would argue.
So I guess I'll need a copilot before I try this. Somehow, I think my wife won't be that interested. She'll say some sensible thing like "Why don't we just go around?"