I had almost the same situation this past summer. Boys state was the same weekend as a church camp (that is VERY important to me). I told myself, I could do the thing I don't completely want to do in order to boost my USMA appointment chances OR go the camp I really wanted to attend. I chose the church camp. I have been told that I am the top spot in my district (unranked slate) but I'll only know for sure after that file close date and when they send out LOA's and appointments.
You have to make the decisions. In my opinion, I would look at your file. If you feel a little uneasy about your grades/leadership/EC's, boys state won't hurt at all. However, if you are a strong candidate, I don't think boys state would be the item in (or not in) your file to make or break you. I'm no admissions counselor though. And that leads me to my next point- talking to an admissions counselor might be your best bet (that's their job). Talk to your regional commander and everyone in admissions you can bother to see if they will hint at how you compare to others in the district. It never hurts to ask.