That's not anything I'd be interested in for an RV. Your RV should already have 1 or more batteries. I'm sure it already has many electrical outlets. All you need to do is install some solar panels on your roof with a good charge controller and add an inverter in your RV. A good 280 watt panel, charge controller, and 1,500 watt PSW inverter would likely cost less than they are selling this "generator" for and would be far more capable.
In short, $1,800 is a lot of money for some very minimal equipment. Building a solar system on your RV would make much more sense.