Re: power leveling
As you have to do all quests yourself, I suggest to reach nightmare Baal and then make Baal runs or just the minions. When you are L70 or so and you have halfway decent equipment (it depends on the character how much of it is needed), switch to hell mode and visit the Pits below the Tamoe Highlands or the Ancient Tunnels below the Forgotten City, maybe plus Pindleskin and Eldritch (act 5). You can also try hell Baal minions, but that might require rather good gear to do at an acceptable speed.