Starting from just along the road from Folkestone Harbour (Google Map) and running straight westwards to towards the promenade at Hythe past Mermaid Beach, Sandgate Castle and Hythe Imperial Golf Course. Sadly the ice cream shops en route will likely be closed...
The 8.74 miles loop is all on wide tarmac and concrete paths, the only hazards being the occasional dog walker, cyclist and seagull. When we have recced the route there was some shingle that had been thrown on the path, and can vary depending on any winter storms, but can't rule that out on the course. The route is right by the sea and it's virtually impossible to go astray, the path is always between the beach and either cliffs, road or buildings.
There are no left or rights, nothing! A couple of slight bends perhaps but its always just straight along the path, straight back to base camp for three loops of 8.74 miles, making the marathon distance of 26.2 (well, OK, very slightly over if my calculations are correct.
You can view the route here... http://www.mapmyrun.com/routes/fullscreen/854243385/
Points of interest you will see
Mermaid Beach : There is a statue of a mermaid somewhere along here, couldn't see it myself I must say, think it may be nearer the harbour, but the beach known as Mermaid Beach is here. It's not very exciting.
Sandgate Castle : This is now a private residence but has an interesting history being part of Henry VIII coastal defence network, then subsequently fortified in the Napoleonic War and WWI and WWII.
Spade House: Sandgate - Home of author HG Wells from 1901-1909
Right at the start there is the Leas Lifts - a tiny tram way to take you up the cliffs. Obviously any runner would just run up the road, but their supporters might like to have a go on the somewhat more sedate mode of transport!