Jake gave us the following advice for playing over those mysterious sus chords
Play a ii- over a v in the bass - eg d-7/g and play d Dorian over it. Then take that through all twelve keys, arpeggiating, playing licks, etc. and you will feel more comfortable with those changes in no time. Also good to play pentatonic patterns - eg d min pentatonic over that same gsus (d-7/g).
In other words Gsus instead of playing G mixolydian play D dorian. Same scale of course starting on a different note. (Steve)