Tony B wrote:
Inside the RV, the connection is exactly the same as on boats and marinas and the other end has the same kind of connectors.
I noticed that some RV's mave the marina styly inside the RV but a totally different connector at the park end. Can I assume this is typical?
The RV end can be most anything appropriate and approved for the application. Twist-lock connectors of some sort are not uncommon (which, I think, is what you're describing as marina style), but there are others, or sometimes no connector particularly for 30A RVs--the cord is just permanently attached to the RV and gets stuffed into its compartment for storage.
The side that plugs in to the campground will always be one of three possible configurations in the US: either a 50A four pin 120/240V plug, the same layout as is used for an electric range; a 30A "travel trailer" 120V plug, which is a unique configuration for RV use; or rarely for very small RVs a plain old 120V 15A plug such as is found on all sorts of household appliances and devices.
You will not find a twist-lock connector at a campground. You might find one on some portable generators, though probably not a 50A version unless it's pretty large generator.