There was alot of water when I was there... The day we went in march in 2006 was like 60 deg. out or so.. it was really nice there was no snow left.. I would not take a daily driver out there... I would not even drive over there... I always trailer... way better.
It does close for a month or so mid march or so till late april early may.. I am not sure though.. You should check with the park for dates or get on wegotmud.com they would be able to tell you also...
Scott.