We also stayed at the KOA in Bar Harbor. One thing to keep in mind is that they do not offer full hookups, at least not in the sites with a water view. The ground, like much of New England, is rock, so no sewer. But they do have a decent dump station. We enjoyed our stay there, and the staff really goes out of their way to help take you to your site, level your rig, bring leveling boards if you need them, etc. Very nice.
Dan & Geri and our rescue sheltie, Casey
2015 Winnebago View 24J