I can't seem to buy recipes from my enchanter dude. Where do I get that currency?
Daily cooldown. You get the recipe when you do the quest that unlocks 601-700 skill. The item that starts that quest is a guaranteed drop during one of the quests out in western FFR, so you should have it by now.
The priest I just leveled to 100 built:
S - Tailor, Enchant, then Salvage at 100.
M - Trading Post, then Inn at 100. Barn is valuable but still too much of a pain in the ass to actually bother with even after the hotfixes imo. Elite beasts are in too short supply and camped 24/7 even on a server like Hyjal.
L - Tore down Barracks for War Mill at 92, then rebuilt Barracks at 100. Don't worry about the iron scraps, you'll get them eventually (dungeons, Talador questing, etc.) and the war mill's loot buff still works before you complete the quest.
Addons: Get Master Plan and Broker Garrison. Broker requires another addon or custom UI that support datatexts. I use ElvUI, and you should too.
There's some other ones that are more optional, like Bulk Orders to queue up the max when you click on a building's NPC so you don't have to spam click the button. Once you have a surplus of GR, BuyEmAll is very useful for buying stacks of dust, scorpions, etc. at the trading post vendor. And I use another one called Work Order Tooltips that uses modified nameplates to remind you the status of a building when you get close to it.