As a wrap for my USGP weekend, I'll post in this thread my facts and figures for the trip:
2 riders (me driving and my best friend in the navigator position), along with luggage, cooler, chairs, and other "stuff" making the trip at probably the max rated weight.
Trip out to Indy, average mpg of 58.2, at an average speed for the 575 miles of 65.1 mph (including all time spent stopped during the trip for gas, food, bathroom break, etc.).
Trip home from Indy, average mpg of 57.1 mpg, at an average speed of 61.8 mph including all stops, and also including at least an hour and a half of stop and go traffic leaving the track for the 620 mile trip.
Total mileage, including driving to and from the track for three days (we stayed in Richmond, IN, about an hour and ten minutes east of Indy) added to the trip mileage from the trips to and from Indy from Maryland, 1,600 miles at an average for the trip of 57.8 mpg.
While the mileage figures are probably on the low end for most Insighters, for me I was pleased given that the car was basically maxed out in gross weight much of the time, and also that we absolutely hauled tail when we weren't sitting in stop and go race traffic. Not really any other cars I can think of where you can cruise at 75+ mph and still get over 55mpg, not even the Civic Hybrid or Toyota Prius can match the performance we saw this weekend.
For a car three and half years old with over 57,000 miles now, I'm pretty happy, and I think that this trip shows that the Insight is a great traveling companion even as it ages! I love taking long trips in my Insight, I just don't get to do it enough anymore.