What you describe doesn't sound a thing like River Road. Cyclists that ride River Road will be found almost exclusively single-file, but one may be on the traffic side of the line falling to the back of the group. If you're "behind some for miles doing 35 because I cannot pass" then you are going down a long hill, not something that is found on River Road. As for bike paths, most of the multi-use paths are still paths to nowhere, and because of their target users (pedestrians and casual cyclists) are pretty much useless to people on road bikes.