I Am A 66 Year Old Male In Reasonably Good

I am a 66 year old male in reasonably good health except for 3 melanoma excisions in the last 6 years. I stay out of the sun because of the skin cancer risk, but want to make sure I am getting enough vitamin D. I have also heard you can take too much vitamin D supplement. My doc has suggested 2000IU for a daily dosage. What is the danger of too much vitamin D and is 2000IU the right amount for me?