Route: Thorney Island Loop (United Kingdom)

Starting from Emsworth train station (nice start/end point) head south and complete the loop of Thorney Island. Either direction, as the elevation will be similarly which ever way you travel as the route is very flat. The island is also home to an RAF base 

“Public access to the island is strictly limited to the footpath that runs around the foreshore (the Sussex Border Path). It is possible to walk either way around the island, as both directions offer interesting and varied perspectives. The path is clearly waymarked around the island; the waymarker sign is a curlew”