Plenty of features that mods have brought to the table are now implemented into the default UI (quest helper included). It's not necessary to install any, especially if you're not taking the game seriously.

STOP TALKING ABOUT WOW.  You're making it very difficult for people who are trying to stay clean.

" Is there a GB guild? "

You should be fine. They've made it so much easier to level. You don't need as much xp per level and if you get bored with questing easily like I do, you can gain xp via battlegrounds now.
 
Once you hit 80, use the group finder to farm heroics. Bosses drop emblems that allow you to buy purples. You'll have a decent epic gear set within a few weeks of being 80.

Don't worry about not being 80. All those folk with a million 80's also spend time lvling alts so you'll almost always be able to get into a group for an instance using the group finder if you get bored of questing!

Use the group finder to do instances as soon as you hit lvl 15.
 
Go onto the realm forums for the server you play and try and find a guild of people who are rerolling chars in  the run-up to cata. You'd be surprised how many people are doing this now that its so easy. I've already gotten a priest and warrior to 80 for my friends in the last 2 months, Levelling is no big deal now. 
 
Addons arent a necessary thing as much as they once were. Don't sweat about it.
 
Keep us updated if you need any advice or anything

n008

play 2 hours per day and you are full gear etc. in like 1-2 months max

Been playing on-off since 2008 or so. STILL yet to get a level 80. Have a level 75 DK right now who i think will be my first 80. So no,..you don't need to worry about much I have fun with it and I've never reached max level.
 
You get some elitists. I remember a month ago or so i got kicked from a dungeon for not having one of my moves at it's max possible level. Problem was I'd only just leveled and didn't realize it...I'd run that dungeon a ton and NEVER had any issues but still got kicked by elitist snobs. IF you can deal with jerks like that which are rare i find then it's great.