Using RAF makes leveling 5 chars from 1-60 quite nice, but after this what is best way to as fast as possible reach 80? Is doing only dungeons most effective?

Another question. So far I haven't tried any arena pvp, but if I later on try out 5vs5 do I need to win to get arena team rating or will I get rating if I just manage to get a few kills each match (even if I lose every match)?