Ah I went by the outer edge of Oort Cloud (heck the thing is as thick as our solar system). So 100k AU at 0.99c and got a something on the order of months. We'd also have to accelerate and slow down so this means only if we fly right by earth and then keep going past the destination. If we go by 0.9999c then we're 10x faster and get there in a few days.