The thing that caught my attention about this unit is that is exactly the size/layout I would like to have, it's relatively low mileage but not super-low, and it appears to be clean and in good condition, from the pics there are. I even like the interior colors.
The price is lower than very similar units, I assume because it's a private seller. Low enough that it would be reasonable to buy a ticket to go look at it, IF I had good information before going.
Then I'd do as suggested and email him for a phone number-ask if we can chat about the RV. Give him a call and see if your questions are answered then. 900 miles is a long way, but if it is rare unit it may be worth it to you. Sometimes difficult sellers (due to attitude, poor communication skills, location, etc) turn off so many buyers that someone who makes the effort gets a good deal.