Run speed is amazing for exploration and staying away from enemies. For deep dives, heavy armor is king. Armor is generally extremely high value and also reduces damage from DoTs in this version, so it pays to have high armor.

At the very minimum, try the pants. All the other leg bonuses suck, and going from -5% run speed to +3% is very nice. The chest piece competes with pierce resistance from root armor, so that's up to preference. Heavy helmets have no speed penalty so +3% speed at a huge armor penalty is a heavy trade.

The fire resistance bonus isn't terribly meaningful when high armor also protects from fire damage. Fire resist is also available as a potion discovered in the plains