I would suggest parking at the Park and Ride on Vine Street right next door or on the street. The gates to El Cap might be open, but I don't know if it's allowed. I'd hate to try it and risk getting my car towed.
They are, or at least used to be always open, but I'm not sure anymore. There is a park and ride as well as the bar across the street from Eastbound. You can also park along most streets adjacent to the rodeo grounds.
That a good question, wish I could give you the answer, sorry 😞
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