I have to disagree a bit with John. If you choose a portable surge/power protector, it goes on the end nearest the power pedestal. If its a permanent install, it goes on the RV end, where the shore cord joins. The advantage of a permanent install is that it's a lot less likely to "grow legs" and walk away.
As for pedestal vs dogbone, it depends on whether you buy a 30A model protector or a 50A. Either one works, even though your RV is 30A only. If you get a 30A surge unit, it will have a 30A plug so it MUST plug into the 50/30 dogbone. If you get a 50A surge unit, then it has a 50A plug and must plug to the pedestal; your 50/30 dogbone then plugs into it. dog bone plugs into it. Buy the 50A version if you think you might someday buy another RV that has 50A shore service. If that's not likely, at least not in the foreseeable future, buy the 30A version and save a few bucks.
Note: Many 50A power pedestals have both 30A & 50A outlets. If so, you have a further choice of not using a dogbone at all. However, the 50A outlet typically is a better physical connection and usually a wiser choice.