I shall answer as best I can...bear with me, it's long, but they are all valid questions I think everyone needs to know before joining an RP so I want to answer as best I can for the benefit of all. 

Firstly the story is very well-developed and laid out...I have run this adventure several times in the past on other forum sites. The longest was a three-year role-play. While the story is generally the same outline, obviously the actions of the characters influence how the story progresses and what details take shape. 

This particular iteration has been underway for 8 months minus The three-month vacation I have to take at the beginning of every year as I do taxes for a living.  We are midway through the first leg of a three leg journey and are at an excellent point to bring in more characters.  The story is a slow moving story, with a post expectancy of about one post per week. More is of course welcome But the current players all have real lives and sometimes it tries to swallow us whole. 

The story is designed so that characters can easily be brought in or removed in a way that actually adds to the story. It is also designed so that incoming players, or returning players, do not feel like they've missed a lot of the story and can join with only a brief rundown of what's happened up to this point. You are, of course, welcome to read the whole thing if you wish. 

While the story is already laid out, character development and the decisions the characters make are very important and I encourage you to develop your characters moral, spiritual, and mundane views as the adventure progresses.

I Will post a link to the OOC later tonight. It has character sheet guidelines, GMs rules, and other nifty stuff. The short answer to the question about skills and traits is that yes, it is limited and divided into class skills and life skills.  In terms of a class system think of these as zero level characters, their class is basically what they want to be when they grow up. It may even changes you adventure...you might find a new role model or something you're really good at that you never even knew existed. 

Any further questions I can answer?