I keep a stack of Cure Serious, Cure Disease, Remove Curse, Remove Blindness, and Neutralize Poison pots, as well as my eternal Freedom of Movement pots. If I'm on a trapper, I'll also keep Heroism pots until I can scroll-cast Greater Heroism, or one of the group can cast it on me. +2 isn't much, but it's still +2. I also try to keep Nightshield scrolls or Shield wands on those who can't cast those spells. Early game is painful when I can't UMD that stuff yet and have to tank Force Missile.
If I'm on a Roboto, I'll swap the Cure Serious for Repair Serious instead. I never run robotos though. Domo arigato Mr Roboto, mata au hima de/ Domo arigato, Mr Roboto, himitsu wo shiri tai!
Easiest way to get to the chests down below is to kill one of the sub-bosses last, after the Wiz King. Then you can drop right down to them. I'm not sure the loot is worth the effort to run to get them.