Go to American Whitewater - RiverSelect
and pick a state. ONce on the state page, scroll all the way to the bottom and click on the "KML" button. This works with Google earth and show the approximate location of all the runs listed in the AW database and also shows whether or not they are at runnable flows. Can't see the East coast all at once, but you can go from state to state to see which has the highest concentration of runs or the Class of runs that you are looking for. Lots of options from western NC/East Tenn, to Wild Wonderful WV to upstate NY.