Go to http://www.longboardmaps.com and you might find some runs in the place you are in or are going to. This might be a very underutilized site, I don't know. But it's there so give some input or use the output of others.
I've got a link to their site from my website. The one problem I see, is that there are too many sites just like it, and they don't allow bike paths as runs, since it asks for cross streets to locate the run.