The Gorham Mountain Trail, just off the Loop Road in Acadia National Park, offers a lovely 3.5 mile run with spectacular rewards for your effort.
The trailhead for Gorham Mountain has its own parking lot, but I prefer to park in an unmarked lot just a few hundred yards past Sand Beach. On busier days in the park, it's even easier to take the bus to Sand Beach and begin the adventure from there. Simply start down the Ocean Path along the Loop Road, heading in the same direction as traffic. This gives you about three easy quarters of a mile to warm up (you'll pass Thunder Hole along the way) before you get to a junction sign for the Gorham Mtn Trail. Cross the street, find the trailhead in the parking lot, and start your climb.
The first few hundred yards feature some legit rock-hopping, but with elevation you'll find yourself on Acadia's signature granite surfaces. This can be incredibly slippery in wet conditions or covered in autumn leaf litter, so make sure you're confident in your skills, your footwear and the weather before you head up.
Although you can take a lovely detour along the Cadillac Cliffs trail, which gets very exposed and technical, if you're looking for something purely runnable you should stay on the Gorham Mtn Trail all the way to the summit. You'll climb about 500 feet in just over a mile to an open summit with gorgeous views. As you climb, take a couple of opportunities to turn around and take in the views that are opening up behind you.
Continue forward on the Gorham Mtn Trail to descend. Again, the granite is sketchy when wet, so take care in the places that don't get enough sunlight to dry out. You'll bear right onto the Bowl Trail, which gets more technical in this last half-mile before you return to the road. If the rock hopping doesn't slow you down, your fellow travelers will. Bowl Trail is one of the busiest in the park, and timing this run early or late enough in the day to avoid crowds will increase your fun.
Bowl Trail ends at the Park Loop Road. Head in the direction of traffic towards Sand Beach (which is in sight) and take the road or the Ocean Path back to your car.
Pro tips:
1. Timing is everything. You'll have a more enjoyable run if you avoid wet footing and the busier times in the park.
2. Turn off your watch. Mountain running happens on its own pace; you're going to stop and take pictures anyway. Acadia trails are so well-marked that you're unlikely to check your GPS for navigation.
3. Enjoy your post-run at Choco-Latte Cafe. There's no better recovery beverage on a crisp autumn day than their Spicy Mexican Hot Chocolate.