I work in Bar Harbor (right on Main Street) and there are several in town locations to park an RV (The one I see is along Main Street right after Park Street). Not really sites so much as permitted RV parking. Labor Day is a busy weekend so get the reservation soon wherever you stay. (My husband and I do AirBnB and charge $70/night and Labor Day weekend was booked in November by our guests.) Re: water view, you will see water views if you go hiking, boating, etc. so camp site views probably less required than the average spot IMHO. :)