As of now, River Road is more appropriate for cyclocross training than for us roadies and triathletes. According to streetsblog.org, work to clear the downed trees will begin soon. Until then riding it is mostly impractical. The exception is the north section in Alpine, which you can access off of 9W. You can still head in near the Police station and do hill repeats down to the Alpine boat basin if you're looking for a challenge.