This deck relies on Bard son of Brand and King of Dale to put Dale allies from all spheres into play. Círdan the Shipwright works well with his fellow Noldor Glorfindel, who he can ready and boost using his ring Narya. Glorfindel can be brought out more quickly by sacrificing cards if To the Sea, to the Sea! comes out early enough. Lindir is currently the only other Noldor in the deck, but others such as Arwen Undómiel, Elrohir, Eregion Survivor, or Sailor of Lune could be included. Putting the Necklace of Girion on Bard will give him extra resources to help pay for non- attachments, since he has to pay for them himself. It also makes him a better quester.
The third hero can be almost any hero, and Éowyn is always a default choice for solo play because her is so high. Lanwyn offers more and has range, so might be preferable for multiplayer. She can also make use of some of the Scout attachments. Brand son of Bain is also a possibility, however he will make it more difficult to pay for some of the Spirit cards, particularly Glorfindel. Including Brand will require some tweaking, and I will probably put together a version of this deck with him in the future.
What I like about this deck is that you can include attachments & Dale allies from any sphere (although for non- attachments, it's best if they're low cost, since Bard son of Brand has to pay for them by himself). 0 cost attachments like Cram and Spare Hood and Cloak might be useful additions, but once again, I don't own those cards! 0 cost attachments will become especially useful if Brand son of Bain is used as the third hero.
The deck name refers to the Running River, which is called the Celduin in Elvish, as seen in the name of the Celduin Traveler ally. The town of Dale, where Bard and Lanwyn are from, was (re-)built along the shores of the Celduin, so I thought this deck could represent Cirdan passing through the region (not that decks need to be thematic, but it's fun to imagine).