The National Park issue seems to be meaningless and apparently that is not what makes the court appearance required. You were charged with a violation of state law:
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§ 3701.1. Leaving an unattended child in a motor vehicle.
(a) General rule.--A person driving or in charge of a motor
vehicle may not permit a child under six years of age to remain
unattended in the vehicle when the motor vehicle is out of the
person's sight and under circumstances which endanger the
health, safety or welfare of the child.
(a.1) Applicability.--This section shall apply to the
highways and trafficways of this Commonwealth and, for the
purposes of this section only, the term "trafficways" shall
include, but not be limited to, parking lots.
(b) Penalty.--A person who violates this section commits a
summary offense. It is a separate offense for each child left
unattended.
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For a summary offense in PA the max penalty is 90 days in jail, don't know about the fines. Same category of the law as disorderly conduct and many traffic offenses, in fact this is a traffic offense.
Can't hurt to speak with an attorney.