Ned planned to support Stannis, and sent a letter to him offering him the crown, and telling him all that has happened, but it was intercepted by Cersei I beleive. Robb also planned to support Stannis initially, until the whole 'king in the north' thing started.
There was never any chance of Stannis allying with anyone who didn't support him outright really. Once Robb wanted the north independent, Stannis just saw him as another usurper, stealing what was his.
I am still puzzled as to when Stannis is going to arrive at the wall. I would think it would be one of the last scenes of this series. Sam didn't send the ravens from the fist of the first men, so he has to get back to castle black quick so he can send them. Davos is already leaning to read in preparation.