Yes, I think both the Swinging Bridge and the Rio are part of Mongaup River and both are reservoirs.. I think Swinging bridge is further upstream and closer to Monticello.
I'd definitely like to get up to the Rio this fall, it's a pretty place and since the shores around it rise fairly steeply, offers good foliage viewing...
If any of you are up to a paddle there for those of us in the lower NY and NJ area, I'm open for it... I know a couple of us VFTTs in the area that do paddle.... Snowshoe, me, Tmax, Bob Smith. All of us are in the general area of Rio and paddle in some fashion.