The trick with a conventional mast style AM/FM antenna, is that it works best with a "ground plane"...e.g. the metal body of a car. But up on the roof of an RV, it's a sore thumb just waiting to be cleaned off the roof. RV roofs make very poor ground planes, because they are largely make of wood.
My PUP has a stubby mast mounted on the side of the 'tub', and it's pretty much useless. But it's down out of harm's way.
These days, many new cars come with a "shark fin" style antenna, and these may have the advantage of picking up satellite radio reasonably well. Their big advantage is their low profile. Tucked in the "shadow" of a roof vent or the AC unit, they'd be out of harm's way.
On an auto, the mast antenna is mounted to solid steel. The problem on the roof of an RV is that the roof is typically rubber (or similar) adhered to plywood. Every time you sproing that thing on a tree limb or low overpass, it really stresses its connection to the roof. Fortunately, if you're not hitting your AC unit, you're within the tolerances of the antenna's flex. What matters is how well it's anchored to the roof.
The disadvantage of a shark fin is that it will be amplified...which means you have to supply power to it. Mast antennae are passive...no power needed. When you pull the old antenna, use the cable to pull your new antenna cable and power wire. Also remember that in a car, with chassis ground, a single wire might do, but in your RV you'll need to pull a pair...for positive and negative.
Here is one example of a shark fin,
but Google to find what's out there.