Steve-
Good topic!
I have my own homegrown simple version of shorepower and a 40 amp charger that I find invaluable in maintaining batteries.
The shore power is chiefly important in heating the cabin at night during the winter, as it allows me to use an electric heater and not my propane powered Force 10 Cozy Cabin Heater, which is excellent, but with the electric 120 VAC connection, it saves fuel and is both simpler and safer.
I have a 1000 watt inverter too, which allows me to use any of the 120 VAC appliances on board, such as the microwave, but it's no worries with the shore power!
I have 4 group 27 deep cycle marine batteries aboard, so whenever I don't have the AC connection, I'm perfectly self-suffiicient, except I have to go back to the propane heater, of course.
My simple "shore power" system consists of the following:
1. 12 gauge three wire (grounded) outdoor extension cord.
2. Adaptor from 15 amp household cord to 30 amp marina power outlet.
3. GFI (Ground Fault Interuptor) unit to protect against shorting to ground.
4. 6-Outlet bus bar with 15 amp circuit breaker and on/off switch.
5. Microwave, electric heater, and 120 v oscillating fan (HOT summer nights).
6. 40 amp battery charger with automatic charging on 10, 20, and 40 amp settings. Also has anti-sulfation cycles and a couple of other gizmos. This is an automotive charger, but kept up in the v-berth where there are no gas fumes and thus no issues with electrical sparks. It's hard-wired into the system.
7. 1000 watt inverter.
8. Honda Eu1000 watt generator.
9. Emergency 12 volt starter pack and light, kept under helm floorboard and always on charge when the boat's plugged in. I plug it in monthly at least.
Wouldn't be without it!
P.S.: My Sea Ray 265 Sedan Bridge has a wonderful shore power system, too.
Electricity is one of the technlogical cornerstones of our modern society and a basic element of convenience in living, just like medicine, prepared foods, water supply, and sanitation. Why give it up?
Joe.