There is a main parking lot with 75 spots. If that fills up, there is a school, Pioneer Learning Center, and a USPS building just north of the venue. You can park either of these places as well because they will not be open Saturday night or Sunday morning. There is also street parking behind the venue to the west if needed.
Yes, the venue allows overnight parking! Same with the USPS building and Pioneer Learning Center.
We will have a shuttle to the hotel in Omaha, Omaha Aloft West by Marriot, leaving at 10pm if anyone needs a ride there. Ubers also reach Fort Calhoun, but make sure to order them early as they will be pretty busy with the College World Series.