[LONGHAIR]

I am a believer in dis-assembly of as much as is practical before cleaning and painting. Anywhere where there are surfaces that are bolted together will hold onto any kind of grease/oil/anti-freeze....and even cleanser residue, plus you have a potential place for the paint to split later. That being said, it is pretty extreme to strip everything and paint the parts while separated, but that is the best way.
Beyond that, warm water and a powdered cleanser called Spic N Span is great for the initial hand washing...prefeably after some pressure washing for the worst crud. After the cleanser, I would go with a work-out on the air-compressor.....break out the blow-gun and hit everything thoroughly. Follow that with some time just sitting to dry-out. Before you are going to spray it, I would go over everything by hand with a proper wax & grease remover just like a commercial paint shop would use. You should be able to get it from an autobody supplier locally.
You have to be meticulous with cleaning/drying or you will have fish-eyes in your paint.