Buy the biggest bag yeh can afford. pickup everything and sell it.
herbalism and miner are 2 great ones to pick.

Dont worry to much about buying yer spells there where times when I didnt train my guys for about 10 levels.

good place to get info on instances is wowhead.com
try out
http://www.wowhead.com/?zones=2#0+2+1
It'll show yeh all the instance sorted from lowest to highest