Rode the Louisville IM course and ran the first and last mile two times before last years race, but it was only a 1.5hr. drive and I had 3 buddies to ride it with me. I changed gearing based on the first ride and made sure it was right on the second. I think it helped me but if I have had to fly somewhere I think I would have got there a several days early drove it and maybe just rode a few segments. Its nice to show up and not feel like you need to get out and drive over 120 miles for a course preview the day before an IM in my opinion.