Do I need an external surge protector? Other essentials?

As has been noted, surge protection is just the beginning. Other protection is more important. I think that low voltage protection is high on the list, especially if you sometimes plug into a household 15 amp plug either at home or in a friend or family member's driveway. The other protections (open ground etc) folks mentioned will also become more important to you if you look closely at how some campground plug ins are constructed.