OK, actually, a decent spot is inside factory bay at Marco Island, back around toward Marco River Marina. Bruce is the dockmaster there if you have any questions. A short cab ride can get you wherever you need to go.
Check the charts
, you'll see it. Follow the seawall/docks around until you're all the way back in the bay, then you'll find decent depth
out off the docks to your S and just W or SW of the houses on the W shore.