http://www.wowwiki.com/Gnomeregan

basically, it looks like there are 6 quests you can have before running. most of them are simple to acquire. i think the -most- difficult is http://www.wowwiki.com/Quest:The_Only_Cure_is_More_Green_Glow, because it has a prereq that looks like an instance quest, but really it's a vestibule quest with an instance followup. so, if you really want to be ready to go w/out having to take a break for turn-in, your log should have these 6 quests:

[26] Save Techbot's Brain!
[30] The Only Cure is More Green Glow
[30] Data Rescue
[30] Essential Artificials
[30] Gyrodrillmatic Excavationators
[35] The Grand Betrayal

i'm about to go do Gnogaine right now so that Brad'll be ready. ;)