I found this video in Google Photos from a few months ago of a flight through The Lake District in England at low level (minimum 250 feet AGL at 450 knots).
The video starts at the southern end of Windermere and finishes at Bassenthwaite Lake, routing via Ambleside and Keswick. Total distance 29 nautical miles. This route is often used for low level in the real world, probably more so than the Mach Loop these days.
You can also see @David_Lockwood flying several miles away.