I heard of this as I pulled into Leverick bay on the day of accident. (I am a pilot). Regarding time of departure, there was plenty of time to make trip and arrive before dark. Distance not factor. Runway length certainly not issue. Winds were generally as expected that day. Often C150 is used as trainer plane or "building time". Most likely cause is pilot error (Distracted by something inside or outside of plane). Potentially banking too much at too low of altitude and causing stall. Could be easy to do looking down/back as plane turning just after takeoff.

Just my opinion. RIP