I mean, root wise, you have something pretty simple:
I, III, VI, II, V, I
But ofcourse, in the diatonic system it would be:
I, iii, vi, ii, V, I
There would be ways of explaining these chords, if they were resolving properly, by interpreting them as secondary dominants:
I, V/vi, V/ii, V/V, V, I
However, my knowledge of chromatic harmony isnt good enough to judge whether or not this is correct. I was under the impression that secondary dominants had to resolve to diatonic key chords (be it in the home key or a modulation)?
SJ