Please try not to be so anxious. Having Crohn's doesn't mean you will be hanging around the ER often. Maybe you will never need to. I have only been hospitalised one in those 9 years with an obstruction, and that was because I wasn't on any meds, and the situation got out of control.
Prednisone may have some bad side effects, but it really helps when you are flaring. It didn't make my stomach hurt, but it really helped me within 4-5 days (stopped the diarrea and my stomach cramps).
For me I know I'm flaring when my stomach hurts and I keep running to the bathroom, I have nausea etc., but everyone is different. Now that I'm on meds, my flares last only 2-3 days and then I'm fine again.
Mucus in the stool maybe a sign of inflammation, but also normal people get mucus once in a while. What meds are you on?