(which is pretty much only danger out there)
I see three dangers:
1. Interdiction in the twilight zone
2. Overheating too close to stars
3. Emergency SC drop to avoid hitting something.
All of them should be trivial, but keeping high levels of concentration up, when the travel is tedious, is easier said than done. I have a routine that pretty much avoids #2, but even so, getting distracted at the wrong time could be a huge problem. On my current trip, I have managed to avoid #2 completely, but have lost 4% due to #3. My problem there is playing 'chicken' with a planet you are approaching. The scanner is ticking away, so you want to stay pointing at the planet to avoid losing time having to go round again, but you may be going too fast to get it scanned in time before you crash.
... on which subject, is anyone else annoyed at the 'slow down' warning? It seems to me to be close to useless, since if you are not already on minimum throttle, you will definitely not stop in time. But I regularly get it when the throttle is already minimised, so there is nothing I can do to slow down.