Thought of a simple solution - just play an archer yourself if you want to be tactical, otherwise leave Janna "standing" well behind while you explore up front. The module is well-balanced, but my paladin seldom gets into so much trouble that he can't make a run for it. And I save often in any case.
I've started playing a Rogue/Fighter in proportion of 1:2 (starting with Rogue). Now a 1 Rogue / 2 Fighter with Expertise, Rapid Shot (Longbow) and Weapon Finesse. And enough skills to disable traps and set them.
My stats are:
Str: 14
Dex: 16
Con: 12
Wis: 8
Int: 14
Char: 12
At some stage I'll switch over to CoT from Fighter to boost my saves, and take advantage ofChar-enhancing items to start using Smite Evil. Not sure if it works with ranged weapons though. Can always switch to my rapier and shield if needed.
So far this toon is a lot more effective than the dual-wielding melee mage that I tried before, who had too many unexpected encounters with high-HP and AC foes to be fun - of course, just after her buffs had worn off.