Yup, I know it sounds too good to be true, but believe me, many people do just that. How? Very easy. First, Acadia is unlike any of the other national parks. It is not one large piece of land, it is broken up into many smaller sections, with private land and town roads in between all those pieces that make up the park.
You may also want to do a little reading up on the geology of acadia National Park, so I will post a link to a cool site on this subject, The Geology of Mount Desert IslandA Visitor's Guide to the Geology of Acadia National Park http://www.maine.gov/doc/nrimc/mgs/explore/bedrock/acadia/igneous.htm
A second reason that makes seeing the park for free so easy is the fack that the park has only one, thats right, one, fee station, and it is very easy to steer clear of it while enjoying the bulk of the park.
In fact - once you pull out of the visitors center off route 3 in Hulls Cove, and continue onto the park loop road, if you don't turn onto the one way section of the loop road, you will never even see the fee station. They placed it mid way along the one way stretch because that stretch of roadway follows the edge of the ocean, for the most part, with spectacular views.
So what sections of the park are free? Pretty much the entire park/ In fact, the entire length of the two way section of the park loop road, which includes the Summit road to the top of Cadillac Mountain, the Bubble Pond area, Eagle Lake area and all the carriage roads, Duck Brook Bridge and all its carriage roads, The Jordan Pond House area with its carriage roads and hiking trails, the Wildwood stables where you can rent a horse or horse drawn carriage, and looking beyond you can access Ship's Harbor and Wonderland trail systems and the much photographed Bass Harbor Lighthouse.
Bass Harbor Lighthouse is very hard to locate if your new to the area, so I will give you a tip on how to find it. Check out the link to view the lighthouse now http://lighthousegetaway.com/lights/maine7.html . You can get stunning pictures of the sunset here in the evening. Go to Southwest Harbor, on route 102. Drive through the village and as you head toward Tremont, you will approach a sharp curve in the road as it rounds the corner, and a sign for route 102A to the left. Turn onto route 102A and pass through the villages of Manset and Seawall. As you pass the Ship Harbor parking lot, you will be entering the village of Bass Harbor. A short ways down the road you will come upon the Bass Harbor Campground.
Here is a link to the Bass Harbor campground. http://www.bassharbor.com/ . Once you get to the campground, there will be a very sharp curve in the roadway, turn left onto that narrow country road, it should have a small sign saying Bass Harbor Lighthouse. The parking lot is small and RV's are not allowed down by the Lighthouse, so park at that sharp corner and walk down to the lighthouse if you have a RV.
Even the very popular Echo Beach with its warm waters is free. In fact, the only place you ever come into contact with a fee station is at one place, along the one way section of the park loop road.
But by avoiding the one way section you also will miss out on seeing the nature center and wild gardens, as well as the bear brook picnic area which overlooks a pond.
So here's a little trick all the locals do as . Drive down the one way section, when you see the signs for the wild gardens and nature center, you can even pull in and enjoy what it has to offer. They have just recently begun to ask for a small fee for a guided tour of this area, take my advice, keep your money, the area is so small and well marked, you don't need a guided tour.
Once your done here, get back onto the one way section, shortly after passing under the stone bridge, you will round a sharp curve - keep your eyes open to the left hand side of the road, and you will see the Bear Brook picnic area. The entrance is very easy to miss, so be looking for it. They have flush toilets and running water, and most of the time, the sites are pretty empty, again, because the entrance is very easy to miss.
There are also hiking trails all along the one way section, so feel free to stop and do some hiking. Once you leave the picnic area, continue on, there will be a couple of pull overs on the left hand side where you can stop and take in the ocean views. As you continue on, you will begin to drive uphill, and the fee station will come into view. Don't panic, approach the fee station, in the left lane, and just before the station, on your left will be a road, turn onto that road to avoid paying the fee. In a very short distance it comes to a four way intersection.
To head back toward Bar Harbor and town, turn left. To reach the schooner head parking lot go straight, it does a loop back to where you are now at. There is a hiking trail here that leads through the woods and to the cliffs with stunning views. If your brave and its low tide, there is also a huge cave down below to explore.
Now if you, like many of us locals, want to enjoy a day at sand beach, or explore the thunder hole area or otter cliffs area, it can all be reached by turning right, and continue down the road. There is a parking lot on the left with hiking trails to great head, which overlooks sand beach, but this parking lot is usually pretty full. As you drive on, the road will end at a dead end, with a rangers trailer on the left hand side. People turn around here in the yard. Before you reach the end of the road, you should see many cars parked along the side of the road. Just park, and walk to the end, and where the road ends, a paved path begins. This path will take you through some woods and into the sand beach parking lot. Okay, I am now updating this, the park service has now cracked down on people using this short cut to reach sand beach and thunder Hole for free. As you drive down this last stretch of roadway, you will come to the Great Head parking lot. You can no longer drive further down the road, as it is blocked off and has signs telling you not to drive or go beyond this point. So you will have to park at the parking lot and walk around the blockade, and down the road for some distance before coming to the paved path discribed above.
Now, if you want to explore thunder hole and the otter cliffs area, go over by the changing rooms, and there is a path which leads to thunder hole, and across the road from thunder hole is a large parking lot, way up in the far corner of the lot is the thunder hole gift shop. The same path leads beyond thunder hole all the way to the otter cliffs. And the total walking distance is not all that great, most small children will have no problems with it.
Yes, by doing this, you will miss out on some of the ocean views, but look at all that money you just saved. And here's the bonus, to see the entire stretch of ocean, catch a free ride on the Islander explorer that leaves the village green every half hour. They will read a message just before the bus departs telling you if you don't have a park pass you should get off the bus now and cross the street and purchase one at the rangers hut by the green. Don't worry none, they don't check people for their passes, it would take too long. What they do instead is the honor system, the bus approaches the fee station, and gets waved through.