Our F350 DRW is 4WD. We have needed it on a few occasions, like Lone Rock Beach (youtu.be/IVJx2T1WJC0), and even one state park. Four-wheel drive isn't necessary most of the time, but it's one of those things that you don't need it till you NEED it. If we ever find ourselves in snow or ice, we might also want it. We like having it and do recommend it as a just-in-case. But, if you're only going to be in RV parks, it might not ever be needed.
Is your truck 4 wheel drive or 2? Is 4WD necessary?