tbh realm of torment was a pain the first time that I went there, but I've done it recently with heroes/henchmen and I didn't find it hard.
Oh and gwen's areas are easily doable with heroes/henchmen, even in hard mode. Some dungeons are nearly impossible to do without several other human players in your group, but the explorable areas are easily doable.
I mainly play paragon and I usually take a variant of sab's build
, a hero build that I strongly advice you to try, it's very effective in pve.