I've been there in October & had a wonderful time. There are certain trails I will not do if it's raining or snowy. Just make sure you adjust your agenda according to the avaliable traction. I ran Gemini, Rainbow Terrace & Long canyon in the rain, it was great.
Easter is crazy down there, but I love seeing all of the Jeeps. Takes longer to grab a bite & hard to get a hotel, but it's like Sturgis, busy, crazy fun!
You'll enjoy October down there!!