I never tried it for your situation but here's a thought...
Try some motorcycle cleaner like S100 Total Cycle Cleaner or Meguiar's Motorcycle EZ Clean. These products are designed to be sprayed on and then rinsed with a high volume water blast after a short dwell time with little to no scrubbing necessary.
Either of these products dissolve and rinse away the road grime pretty effectively on their own. Obviously there are limitations but I think your frame and chassis components are a good candidate.
Short of manually cleaning with brushes, rags, etc., I think the Motorcycle Cleaners have a pretty good chance to provide acceptable results.
I'm almost certain that AG sells either of the products I mentioned.