You don't really need the 90-100 upgrades anyway, Draenor flies by quickly. Just make sure to move on to the next zone in increments of 2 levels.
90-92 = Frostfire
93-94 = Gorgrond
95-96 = Talador
97-98 = Spires of Arak
99-100 = Nagrand
Go after garrison-related stuff, with followers and their quest lines, the experience comes with it. When you're pre-100, having a lot of followers helps because they can do missions that give
youexperience as well.
The
WoWhead follower guideis a pretty good reference.
Frostfire = I usually go after Dagg, Mulverick, and Weaponsmith Na'shral since they have easy quests to obtain them. I've picked Greatmother Geyah for three of my characters from the canyon questline and 2 of those times she rolled with Scavenger trait.
Gorgrond = I go after Blook and Tormmok almost immediately. They come with awesome abilities (warriors are way useful on missions). I go after Penny Clobberbottom (she comes with the Massive Strike ability, which is great). I usually pick the Lumber Mill garrison outpost for usefulness and Kaz the Shrieker rolled up with the Scavenger trait 3-out-of-4 times for me.
Talador = I after Aeda Brightdawn, Ahm, and Pleasure-bot 8000 right away. I tend to drop Pleasure-bot later, but he fills a slot early on. I pick up the Arsenal for the garrison outpost because Morketh is a warrior (which is awesome), and the Arsenal's AE nuke/stun ability rapes everything while questing. Just round up mobs and drop the bombs. You can mow down elites and save your ass with it. Go after Soulbinder Tuulani's questline, as she is one of the rare followers you can get with Group Damage counter outside of the Inn.
Spires of Arak = Follow the questlines, but make sure by the time you get to the Axefall part, you run out and get Leorajh (another rare Group Damage AND he's a bodyguard), plus Benjamin Gibb. Gibb is a badass DK tank and if you do Garrison Invasions, grab him on patrol for it. He absolutely decimates everything by throwing Death&Decay everywhere. He's easy to get, go to the ghost Alliance town across the street from Axefall and run all the way to the back, you'll see him buried in the graveyard. Go to the goblin town in the southeast for Kimzee and the Salvage Yard quests (a requirement imo). Pick the Inn for your outpost to get the Dark Ranger, the trade post sucks.
Nagrand = You might have a ton of followers by now, but they'll throw Lantressor at you. Goldmane and Abu'gar are both useful and pretty easy to get. Abu'gar is a tank so that makes him useful. Goldmane is a skinner so he can be useful for the Barn to farm Savage Bloods, now that they can be increase by follower.