Where do most people level with an 85 heroic? Dead Hills still a thing? Also looking for spell/AA rotation at 85. Thanks!
I would probably do quests in feerrott and lower house, to get a basic aug selection, and the mercenary-upgrade. Maybe even continue with progression taking the expansions in order. Probably not the fastest way to max level, but it beats grinding the same thing over and over. Alternatively you could skip straight to TBM-HAs(after the feerrott-merc-quest) and work on unlocking the gear vendor and grind remnants(HAs needed for dicho-upgrade anyway). As for spell/AA rotations, that depends on which class you are...there are probably some heroic guides in the class-forums.
It is nearly impossible for a single character to do The Broken Mirror heroic adventures. After the recent changes they are hitting harder than equivalent monsters in VoA. So that's not an option unless you're doing the box.