Depending on what gear they started you with, probably not.
Time spent on old quests will build rep with old factions. You'll want to build rep with
Cataclysm factions so that you can get the appropriate shoulder inscription and arcanum. Gaining rep with those factions will also open up dailies and maybe some useful gear. Getting the early quests for a zone out of the way will also let you buy a faction tabard so you can get rep from random dungeon runs.
With that said:
You may want to start with Mount Hyjal instead of Vashj'ir. A later patch added Firelands, a zone that offers nicer stuff at 85, but you have to clear a good chunk of the Mt. Hyjal quests to open it. You'll also want rep with their faction for the caster's arcanum.
Deepholm has the quest lines for your shoulder inscriptions. Do it as early as you can, unlocking the vendor is annoyingly lengthy.
Watch for the quest line where you save Thrall, which starts with
The call of the World-Shaman. You'll probably want the cloak at the end of the chain to help you improve your iLevel.
Run random dungeons early and often. You'll probably have a few frustrating PUG experiences, but drops in instances are usually nice. You can use a tabard to build faction rep, the money is OK and it is easy to get the quests (which pile on more XP, rep and rewards). Overall, the benefits should outweigh the PUGs, although sometimes it may not seem like it.
Yes, Rhode is annoyed at PUGs this weekend.