Dish Playmaker

I can't help with which mount to get but a mount that doesn't impeded your ability to get on the roof would be a good idea. I have a bicycle mount on my ladder and I'm so glad I got one I can swing out of the way so I can climb the ladder without it being a problem.

If there is a ladder mount, there will only be one and it will be made by the folks that built the Playmaker.

I see two problems. One, this antenna was never intended to be used while under way so it will lose track of the satellite if you are driving. Two, for the same reason, if parked and you don't have a solid leveler type support, only walking around in your RV may cause interruptions in your satellite connection.

A ladder mount does NOT assume it will be used under way. It's just a convenient place to keep the antenna and when you park, it's ready to go. It's very rare that moving around in an RV will cause permanent loss of signal or even temporary loss. There is actually a fairly large cone allowing for movement without loss of signal.