I doubt you'll have any issues on course. Pungo is a 70 year old airfield, though the concrete is in pretty good shape for its age. It's not "smooth", but smooth enough for open wheeled race cars with less than 1" of ground clearance to run.

Here's some video I took earlier this year that shows the conditions of the course:
http://www.youtube.com/watch?v=szXx5w2hJiM

I think your biggest problem would be the unpaved road into the site, which is rather rough. If you can make it through that, you should be fine.