Spoiler Alert!I made my way through route 23 avoiding as many trainers as possible. I got Flamethrower and taught it to Camerupt and Manectric. When I got to the beginning of Victory Road, I didn't bother healing because I had only had a couple of battles. I charged through Victory Road battling only the 4 necessary trainers (5 if you count Hugh).
Before I attempted to beat the E4, I stocked up on lots of healing items (revives, full restores, max potions).
I beat the E4 without too much difficulty and battled Iris.
I beat her Hydreigon, Lapras and Aggron easily. Then she brought in her Focus Sash Haxorus. It Dragon Danced and swept my whole team.
I decided to do some extra training before I attempted to battle Iris because I knew her Haxorus woule be a pain in the ass
I levelled everyone up to Lv. 69 (please excuse my immaturity) and I am currently waiting outside the E4 about to enter.