I'm about to leave for BLC. How difficult a school would you rate it?

This is of course a subjective question and possible answers may prep you for success, as well as failure. Regardless of level of difficulty others may have, or their level of annoyance, or their past, present, and future capabilities; it is recommended to go into any course the Army sends you to and learn as much as possible. One ideally will want to stay motivated and focus on coming out with additional knowledge of how to lead in a complex world. It is not recommended to go in there with any less attitude than coming out doing the best you could. These schools are here to develop us and anything mentality less than doing ones best is unacceptable. With that being said, remember why your there but by all means, have fun and make connections with other leaders.

The most difficult things you will have is APFT and map reading, if you are proficient in both you will have no problems. but keep in mind that there is much more than those two areas you will face.

I can't speak for BLC but when I was in PLDC is was not a "pay attention you will be fine" type of school. Our group graduated with less than half from what we started with. That being said, most people got dropped after land nav and their PT test so if you can pass those like every soldier is supposed to anyway, you'll be fine. Good Luck and Congrats.