Same here, but after 2 replacement front engine covers I coated the alternator belt cover steel screw threads with 'starbrite' liquid electrical tape before screwing them into the aluminium cover, and touch wood, she is still looking good (Plenty of FS365 used too). The cyl head covers are holding up okay, maybe the original paint was poor quality ?
After riding on salty roads, my advice is:
COLD water hose to rinse off salt deposits. (Hot water liberates salt and makes it worse so avoid at this stage.)
Coat bike in dedicated spray-on bike cleaner (I use Hein-Gericke brand).
Wash clean with stiff brush and warm water with "Wash 'n Wax" in it.
Cold water rinse using hose.
Use Garden Vac on blow to blast away excess water (good trick)
Coat in FS365, spray WD40 onto switchgear to protect (or whatever preserving fluid you use), especially in hard to reach areas. Obviously avoid spraying onto brakes.
Store under cover (mines garaged).