restoring the shine

I have decided that the next project will be painting the bottom portion of our motorhome which is galvanized then sanding and buffing the fiberglass. I sanded a area around 18" square starting with 220 and worked my way up to 600 then machine polished to a real nice shine. The sanding was with a 5" orbital, looks like a month long or more job but like the way the sides come back to life. The end caps don't look near as bad as the sides being that its a nicer gel coat job. Almost thought about painting the whole thing. Ouch , anyone else done the same?