Alternatively.

Scholo 37-42

BRD 42+

BRD is really very good now, my basic run is to clear the main entrance area + the loops, moving the lowbies into the area so they don't miss xp. Then run to the shadowforge gate or whatever and take the door into that area. Close the door and clear all the way to General Angerforge. Run back to the big door drop down into the semi circle area with the dorf packs on the opposite end as Bael'gar. Clear out towards where your lowbies are and run them down through the shadowforge gate, then clear to Bael'gar. Reset. It is HUGE xp and will get you into your mid 50's very easily. By 53-54 I'd probably switch over to lower BRS until ramparts.