Using kicks-scripts for questing 1-90, it takes me about ~5 days playing 24/7. Questing is very safe as long as you set your bot up correctly. My characters (tauren druids) all have guild xp bonus and 25% bonus heirloom increase from the guild heirlooms (hat/legs/cloak) by level 15 or a bit lower. It also helps to put about 500g (for mount training/repairs/food) and Embersilk Bags to save time also (Embersilk is worth the extra gold over netherweave if you are going for speed). There are a few places I notice the profile will hang up so I check it periodically, also there are a few quests that require user assistance starting around uldum I believe. If you plan to bot 24/7 and already have an 84 paladin though, I would just level that to 90 and use that to farm to save time and start making gold that much faster since 24/7 botting will lead to a ban.