What you can do that may help out is take your time driving around all three islands without destroying any stands, keeping the timer from starting. This will allow you to have all nine (five in Staunton, two in Shoreside, two in Portland) on your map before you begin. I suggest starting from either Portland or Staunton and working your way across the city; if the traffic from bridge to bridge is too much for you, you can always plan a route through the Porter Tunnel, though it can get pretty messy down there too. But as long as you weave through traffic (I suggest using the handbrake for sharp turns) and keep a good pace, you should be fine. I usually finish the mission with at least 3 minutes left.
By the way, about that last stall you're looking for: look near the hospital