First 100

I am training for Burning River 100 this July, and it will be my first 100. I am starting to get really nervous!! The I have ran 50 miles before, but it's been about a year since I have done that. I have been running consistently, approximately 50 miles, sometimes more a week. By mid-June, I will have run 3 50k's in preparation (one in March, one in April, one in June). What is the longest long run I should do? Is my mileage adequate?? Any advice would be appreciated!!