North America
Trans-Catalina Trail
The Trans-Catalina Trail is a 37 mile hike, although you can just hike one of the segments. Bikes are allowed on 8 miles of the trail.
Learn more about trails from the Catalina Island Conservancy. You will need a hiking permit.
Catalina Backcountry can help with equipment and logistics. Safari Bus can provide transportation between trailheads.
You can reach Catalina in about an hour via the Catalina Express ferry that embarks from San Pedro, Long Beach and Dana Point.

Bizz Johnson National Recreation Trail
The trail follows the Fernley and Lassen Railroad in Lassen County, California.
Marvin Braude Bike Trail
This Southern California bike trail runs from Torrance Beach to the the Will Rogers State Beach Santa Monica, mostly right along the beach. You must ride along Washington Boulevard through Venice, Fiji Way in Marina Del Rey, and Hermosa Ave in Hermosa Beach, but the rest of the route is on a separate bike/pedestrian/skater way. The trail can be very crowded on weekends, and in some areas on weekdays.

August 21, 2017 US Eclipse
Parts of the United States will be treated to a rare total eclipse on August 21, 2017. There will be many wonderful place to watch this incredible show. Find the NASA interactive map of the eclipse here. If you have never seen a full solar eclipse, you must.

I will view it in Grand Teton National Park.
Great Allegheny Passage
The Great Allegheny Passage is a wonderful trail that stretches from Pittsburgh Pennsylvania to Cumberland Maryland. Much of the trail around Pittsburgh is paved, but most of it is a smooth double track. Much it is a converted railroad route along the Youghiogheny River, so the grade is easy and the scenery spectacular. Instead of riding up and down hills when crossing a valley, the trail has beautiful long bridges.
My favorite part of the ride was from Connellsville to Meyersdale, most of it heavily wooded. The trail from Meyersdale to Cumberland quickly crossing the continental divide, followed by a fast ride downhill and through some long tunnels to Cumberland. At Cumberland, the trail connects to the C & O Canal Towpath that continues on to Washington D.C.
For a one or two day ride, I recommend taking Amtrack to Connellsvile. You can ship your bike, or rent one there. There are plenty of places to stay and eat along the trail, so you don't need to carry equipment or food. The trail is especially beautiful around Columbus Day when the leaves are turning. Learn more about the Great Allegheny Passage here.