Just based on what I like in vehicles and whats on the list, I'd be most interested in the Fords with dual rears. No gas engines or single rears.
Good to see there aren't any 6.0 engines on the list. They are turds best avoided especially for us DIY-ers. The 7.3 is a great motor and probably the easiest to work on and get parts for.
I'd scratch the gas ones off the list. Diesel is the way to go for moving something heavy.
7.3, dually, with no rear ac is what I'd be after.
Also avoid rust. Rust is the plague for some of these and its a lot more work to fix rust than it is to look for a cleaner bus.
check the frames and chassis for anything more than a bit of surface rust.
If you're flying in just to look and the seller knows it then you are a disadvantage. I'd at least surprise them by acting a bit nonchalant and dickering with them on the prices. Also I like to wear my full "blue collar" getup with work boots, IHC t-shirt and levi's. I like to have grease under my fingernails when dealing with sales or service of vehicles.
Taking my old school redneck trucker dad with me also helps to keep from being ripped off. Especially at tire shops and the like.
There's my 2cents for you. Best of luck and I hope you enjoy the trip. Be sure and get pics for us here!