Southwest Saskatchewan is often overlooked, which can be great thing if you value some solo time in nature and history.  Grasslands National Park covers an area of 907 km² (350 sq mi) and was developed to protect grasslands – one of the most endangered ecosystems in the world.  The park is considered to have the most diverse natural sounds and the longest stretches of time without man-made noise, of all North American grasslands, and is designated as a dark sky preserve. There are thousands of archaeological areas within the park, including over 12,000 tipi rings.

From traillink.com:

The Blackwater Canyon Trail follows one of the most challenging and picturesque segments of the former West Virginia Central & Pittsburgh Railway. On its 10.7-mile run deep through the Monongahela National Forest in eastern West Virginia, the rough dirt trail passes waterfalls and relics of the railroad and coal industries.

Located in Sleeping Bear National Lakeshore, this is arguably the premier sand dune climb in North America! The FKT Route is 10 laps up/down (or down/up).  The vert on this compares favorably with other iconic hillclimbs, even in the mountainous west, yet this route offers a swim in a huge blue lake at the bottom and the joy of running downhill in soft white sand.  This is a popular and contested Strava segment, and really worth doing, regardless of your time.