The cracks are in the fiberglass surface itself, buffing them may work for a while but the only real cure is to replace the whole side panel. Our '02 DSDP started showing it in '04 and Newmar told me buffing it would cure the problem. Well, it didn't and by that time it was out of warranty and would cost about $18,000 per side to remove, replace and repaint. Not worth it to us. The spider web cracks were still there when we traded the rig in 2015.
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft
Charter Lifetime GS Member, SKP, FMCA,
RV'ing since 1957, NRA Benefactor Life, towing '14 CR-V