Just remember if you run the companion by itself you will not get 26.6AMPs out of it. Only 13.3AMPS. It will not run 26.6AMPS unless you have two 2KW Hondas connected together.

I don't know what the difference in cost is between the two units but you can do the same thing with the standard EU2000i by getting a $12 RV30A-15A dogbone long adapter from WALMART and plug it into the 120VAC receptacle on the EU2000i... Might save some money until you get ready to have both units.
Actually you might want someone else on here that has the companion to state if you will get anything at all on the 26.6AMP Socket if you are NOT running two connected together.
You need to have one of the RV30A-15A adapters anyway to plug your 30A Trailer into a garage or some other 120VAC Receptacle somewhere in your travels.
Roy Ken