Warren,
I have purchased ALL the past options in order to find a combo that would work on the boat, on the field (farmwork, spraying, etc.) and for the farmhouse (2 combined gensets). I am anchored out right now, but somewhere at home I have all the instructions. I am pretty sure you can read the manuals from Honda online. I did not get good info from the local Honda dealers in Wichita a few years ago when I was first searching.
The two simple cables allow you to plug in a variety of different 110V, 20 amp plug-ins, but limit the draw from each receptacle in a kind of complex pattern.
The yoke I bought has the twist lock, 30 amp connector, and it works great for the boat's marine power cord (30 amp twist lock). I bought an adaptor connector from twist lock to 30 amp RV for emergency use, but the diesel genset on the motorhome now has never failed.
So, I would order the 30 amp twist lock version. That is the most stable and easily adapted to the RV straight blade plug receptacle. If you got the RV straight blade receptacle, you could still adapt it to the twist lock, but the RV blade junction is not stable and loosens easily on a boat - and is less water resistant.
Right now I am at anchor up on the North end of Grand Lake, OK and it is in the low 40's outside with 30-35 mph winds, but I am warm and comfy inside the cabin (Wallas)with the Honda 2000i running on Economy mode just to run the computer, radio, and battery charger. Only on hot days running the A/C or running a 110V heater or microwave oven, 110 V coffee pot do I need the high speed on the genset.
I use a 12V coffee pot which still runs on low speed economy mode on the genset since the battery charger is slowly replacing the juice used by the coffeepot.
Another nice thing about the old Yoke setup is that it gives you extra, strong rails to hold the genset in place.
JOhn