They do love squeezing into tight spots, don't they? Neither spot looks safe to me....She could get stuck under that filter, or stuck/burned by the heater..I'd raise the heater up a little, or at least position it on an angle.
If the tank has enough room, why don't you buy one of those hanging plants? My guys love climbing and squeezing between it and the tank, but its loose enough that they can't get trapped:
It comes with a suction cup so you could attach it to the back wall, and trim it to fit:
I got mine from a local pet store (6.99). I think you could get it at Petco or Petsmart.......