Single or Multiple Characters?

[HoneyBiscuit]

However, are a single character able to have all the different jobs, will there be enough quests to level all of the classes

You get an experience bonus (known as the "Armoury Bonus") of up to 50% when leveling another class. In order to get this bonus you must have a class that is higher level than the one you are leveling. If you have gladiator at level 30 and begin leveling conjurer to unlock paladin, you'll get bonus experience so long as your conjurer is a lower level than your gladiator.This bonus applies to all monster kills and levequests, and stacks with your rested bonus of 50%. In case you are unaware, rested experience is built by hanging out, in towns and camps. You'll see a small crescent moon on your experience bar when resting. You can also continue to earn rested experience while logged out. Leveling an alternate class with 100% or more bonus experience is pretty quick, and a benefit you won't be taking full advantage of leveling an alt.

It's also easier to gear your other classes than it is another character. Rolling greed and getting armor/weapons that aren't for your current class can actually be put to use.