Only advice I have is do not take 81 into Binghamton; get on 15 south of Harrisburg. With the exception of a short stretch of two lane road it is new pavement most of the way and an extremely nice drive. Took us about 10 hours from the I64 I81 junction to our home which is an hour north of Elmira. I don't drive over 60 and stop on the schedule of my wifes bladder. I86/Rt17 between Corning and Elmira is probably the worst pavement in the nation. You won't be on it that long and can more than likely route around it with Elmira being your destination. Your time may vary.
Dixie Caverns is certainly not a destination site. It is good for an overnite. Bathrooms although reasonably clean haven't been updated since the Johnson administration. Very easy on off for the interstate.