I've been playing with the usatf looking for some cool runs and decided to see how bad it would be to run across Hong Kong. I was shocked at how
tiny that place really is. Because the train ride to SZ seems to take forever.
Anyways, It's about 26 mile in a direct line so you add about 5 miles to that due to curved roads and stuff. Basically start at the SZ border train station and run to the edge of Stanley Bay. The only draw back would be getting ran over I guess. Macau is too easy but I've been eying Taiwan too (won't be a single run of course).
http://www.usatf.org/routes/map/ to see the distance.