I felt one of the mistakes I made when I first started GMing was that I had a Linear plot set in mind for players. I now try to keep things more open and not try to force them down the plot I have written up. I try to anticipate what they are going to do, so I'm not blindsided as much, but when I write up stuff now, I usually include a few options for the way things could possibly go.
Same with me, I try to do more open runs now and anticipate things, but even then I get blind sided all of the time. And since I'm OCD about having good maps for everything it causes me to almost have a panic attack when they are trying to hit a scene I'm not prepared for (I can do a real quick one but it isn't up to my standards).
So now I find myself with about 10 extra maps on Roll20 that I made just incase they try to do a scene I'm not planned for, I can match it to what works best.
But the key to ShadowRun GMing is flexibility i think.
mind postin your map archives somewhere i might use them in a pinch?
I don't think Roll20 allows that (at least without the premium version), but even then I think it would only give my account access to the maps across my campaigns.
But I just end up putting together random maps together when I get bored at home.