(By the way, I did find this all by using google's site: syntax here. )

According to this thread, Skuggo got his PL'ed to 58 in a little over 3 days /played before RAF bonuses. My average time with my 5-man RAF teams lately has been a little over 2 days /played to 60 by very casually doing quests, no instances and very few collection quests unless they're easy and lead to more quest chains. So, I'd suggest whichever makes you happy. Personally, grinding instances over and over and over ad nauseum makes me want to /wrists, so it's all questing for me with the occasional 70 boost through an instance ONCE to get the quests done in it.