Dorna and Xanos do not appear in HotU.

By the way, those annoying electric traps in the tomb can be discharged with the helmet of discharge (which is found fairly close to the entrance, I believe)

Ah! Ill try that today and then switch henchmen and see if that speeds things up. thank you!

You've gotten good advice in general.

The "standard" Sorcerer feats are...

Silent (or Still) Spell
Empower Spell
Maximize Spell

Those allow you to cast a given spell at multiple spell levels. It's also common to pick up (Greater) Spell Focus in one or two schools. Evocation and Necromancy are the most typical.

But...it is also environment dependent -- I've seen modules/worlds where Spell Foci in Evocation and/or Necromancy would be a waste (because everything has insane reflex with Evasion and/or is immune to death magic).