Sugarcreek Metro Park, in Bellbrook, OH, has a variety of trails. The longest hiker trail is the 5km Green Trail. It makes a good route for multiple laps. You may run either direction. The park map is here: https://www.metroparks.org/wp-content/uploads/2016/01/SugarcreekMap_03-2017.pdf
Singapore Round-The-Island.
Course primarily follows the coast of Singapore according to a long establish but unofficial cycling route. The southwest corner cuts out the Tuas industrial/port area. The route can be completed from any starting point but all variations should take in the following (clockwise from 12 o'clock):
Woodlands Checkpoint
Woodlands Waterfront Park
Sembawang Park
Punggol Island
Punggol Point Park
Coney Island
Pasir Ris Park
Turnhouse Park
Changi Beach Park
Changi Coast Track
Just a 10-minute drive from the M4 and Swindon, the Aldbourne circular route tours the North Wessex downs (Area of Outstanding Natural Beauty) and The Ridgeway on rolling hills in untouched countryside. Being so quiet but easily accessible, it makes a great place to zone out from day-to-day life. Doctor Who scenes have been shot in this village. The route begins in the village of Aldbourne which has spaces to park your car and two pubs for post run refreshments!
The route runs the whole of St Brides Bay on the Pembrokeshire Coastal Path, and covers some of the most iconic sections of the Pembrokeshire Coast National Park including Ramsay Sound, Solva Harbour Newgale Beach and Broad Haven. Keep your eyes peeled for some of the route's wildlife such as grey seals, gannets and puffins.