As to the VHF Marine, most Marinas pick one channel and stay there.
A little [3-4 mo's] monitoring and logging should work to figure out the marina traffic.
However OPS [Cargo, Fuel, Tugs] can and does occur on a multitude of the channels. I've found it best to enter ALL the VHF Marine channels, and NOT just the US, as you will get visitors from other countries and they don't all stay on the US Allocations.