I work near Grand Central and run at lunch time south along the East River (you can't really go north yet). It is ok but if you can get up to Central Park it would be better.
Yes, Coogans is worth visiting - take A train to 168th St. If you venture up there you should definitely go to the Cloisters Museum inside Fort Tryon Park. It is a few stops further uptown (190th St) from Coogan or a decent walk. Look it up - the views from park are amazing and the history inside the museum is beyond words.
Thanks, I always wondered about the Fort Tryon/Inwood Park area. Perhaps I will make an effort to go up there if I have a day to myself.