Black

Hudson River Rafting Company is probably the outfitter above Hole Brothers that they were referring to. I'm sure if you ask nicely (bring PBR) they'd let you put in. The outfitter further up is not as receptive to private boaters using their put-in, which in my opinion is a little cruel considering that is the only sane access point to run Club House Turn and Burn's Wall. It's also bogus that they told someone the Black River is not open to private rafts. Private boaters are not only welcome on the Black, but more should make their way up to paddle this gem that has reliable flows throughout the year.
It's impressive that you made it down Great Falls solo in a raft, I've never heard of anyone else doing that.
If ever you are in need of beta for the Black, stop by the rafting bases, the other ones I mean...