Take it from us who played in the 2.X days. About every 5 levels you spent a day to get 2 more to continue the MSQ. At least now the only thing holding you back is the MSQ itself. And if you hit say 52-54 during the 2.X MSQ more smooth sailing thru HW, get to 62-63 from HW MSQ smooth sailing into SB, and you wont have to worry about grinding til probably around 67-68.

Edit: I'd say 2.X grinding sessions started around lvl 23-27. Let's be fair, Road to 60 does nothing substantial to the 1-19 leveling process.