Prepsol usually takes the yucky black goo stuff off. If you can wax the paint again after you prepsol it, as prepsol also takes wax off, which protects the paint.
As for finish, you can bog if you want, or you can just primer (and or cold gal) and paint it, up to you.
Wire wheel depends what type and quality. You can also try flapper wheel, personally I prefer these but they're more expensive.