First off, this is my first time ever GMing a game. In fact, this is only the second time I've ever played a tabletop RPG in my life (I played a few Shadowrun runs during November and December of last year). The rulebook is in the mail along with a GM screen and dice, so all I really need is the paper and pencils (and character sheets), and I'm all set.
What I really want to know is, is this idea a little too ambitious for a first GM campaign? So, I decided to pick Baltimore as a start point. The runners who are participating start off running from a group of gang members, who are chasing them after a botched run. After a short chase sequence (to set up how they get to Baltimore), they either make it to Baltimore safely or barely alive, depending on skill checks. From this point onward, the game is a completely open world. I plan to use a section of a real map of Baltimore as the setting, and populating it with my own buildings. The main goal of the campaign is to get out of Baltimore and (if the players choose) track down the gang that landed them there in the first place.
Okay, sounds ambitious enough with the real life map right? Here's where it gets tricky. I don't know much about Shadowrun lore at all (the last GM just ran a few gang runs and that's it). In my campaign there will be 3 main gangs that dominate Baltimore's streets. Each gang will have their own questlines, their own trust meter, their own leaders and personalities. It's up to the players which one they work for (or betray eventually). Think Grand Theft Auto 2 (Respect is Everything!). So I'm thinking of writing an overall storyline that pieces together inbetween the 3 gangs (and working for only one just gets you one piece of the puzzle). So, if need be, there will be betrayals, or, recruiting NPC deckers to crack into secure databases (which will cost a hefty amount of Nuyen).
Trust will be earned with favors or successful runs. The more the players gain a gang's trust, the higher paying, riskier jobs they will receive. I'm thinking of anywhere from 20-50 runs per gang. That's 60-150 runs total that can be done (but highly unlikely in one playthrough). Trust can be lost by attacking gang members, failing tasks and runs, and if the gang in question finds out you were working for a rival gang. In order to keep a balance, the players will either have to remain stealthy or pull off consecutive small jobs so that the attention doesn't turn from rival gangs to the actual runners doing their dirty work. If a gang suspects that the runners are allying with a rival instead of freelancing, they will set out to shut them down by any means necessary.
On top of the gang missions I will probably make a few side quest situations that the player characters can get into with various NPCs around the map. Of course, the players could just strike out on their own, abandon their jobs as runners and start their own street gang, running drugs and taking territory. As I said, this is going to be an open world campaign, anything goes. The storyline is there if they want to follow it, and the way the players interact with the world will shape how they reach the outcome (or if they die trying).
So to recap, 3 gangs, a trust system that determines which runs can be taken, 60-150 runs for the entire campaign, side quests, a real section of the Baltimore map with multiple locations and NPCs. So, does this sound too ambitious for a first-time GM? Hell, even a first time reading through the rulebook? I think I might be getting in over my head here, but I just want to know if this sounds like a feasible idea here.