Most quests in VR are not against your faction, most are against internal enemies and dangers. You probably have to fight some against your faction to do the main quest line in some zones but not the majority and this is limited to a few quests.You don't 'have' to run quests at any level (although you have to complete story mode to progress in VR)
Dungeons, grind, or PvP will still get you to level 50. Dungeons, trials, PvP and grind will get you to VR12.
I'd recommend NOT questing once you reach VR as it will screw up your game if you want to run an alt or remain loyal to your faction