There are several areas with on-the-Fairgrounds parking -- $15 in large Parking lots near the Coliseum and the Livestock barns/Pens.
They are a bit pricier to park than some of the areas outside the fairgrounds, fenced in and pretty well staffed and managed.
If you have access to the DART Line, there is always that Option as an efficient way to get to the Fair and leave your car in other areas of the City.
About 20% of Dallas Police force are patrolling and monitoring the Fair Grounds and immediate areas, so it is relatively safe.
There are multiple methods to get discounted tickets to the fair for different days and times (look online for best available prices).
A ride on the Ferris Wheel at night gives you a great view of lit-up Downtown Dallas.
Fair Park truly is a National Treasure of Art Deco buildings that deserve to be loved and enjoyed year-round, not just during the three weeks that the State Fair is the major tenant. Major buildings require continual renovation and upkeep to keep them fresh and pass on as Architectural heritage to future generations.