Mapping out shell beach - st malo through lena lagoon?

So first - thanks everyone for the help yesterday about launching from Bayou Segnette. I am planning on fishing 5-6 trips over the next 2-3 weeks and that will definitely be one of them now.

To today's question - I have never been to shell beach, but want to go there on a trip soon. I was looking at the map, and I plan to launch from Campo's marina. For a relatively short/close trip through the marsh, I was looking at:

- Launching from campos
- Going into Bayou St. Malo from Lake bornge
- After getting out of the main St. Malo run, then fishing on the trolling motor on the way to lena lagoon (heading south). It looks like there a few ways that Malo connects to Lena lagoon and they look wide enough that they shouldn't be incredibly shallow
- Fish through Lena lagoon to the end by the mrgo
- take the mrgo back to the launch

Does this plan sound reasonable? Will there be a bunch of boats running at speed through st malo that would mess up trolling through there?

Thanks for any help.