From glacier peak, the only other descent down (besides going back to Georgia pass), is down Missouri Gulch which does connect at the bottom to the Middle fork of the swan.
I'm not sure at what point it dead ended for you. Do you think you could have missed it? Did you descend the steep rock garden. You would have had your hands full going down it with stock vehicles. I made it up this garden a month ago and I had my hands full for sure. Now that I think of it, running boards on stock rigs, would have been pretty well destroyed.
Scott Yoder KD0DHP
2000 4Runner, 2.5" lift on 33's, locked, geared & armored.